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One-to-one · Connecting mailboxes

Connecting mailboxes

One row, in depth: what each tool does, the verified numbers, and who each suits.

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Mystrika details read from Internet Archive copies of its own pages (home page 11 October 2026, product and use-case pages 10 July 2026, help centre and tools pages from 2024 to 2026), because mystrika.com refused automated reads on 22 October 2026.

Warmerly

Google and Microsoft sign-in, Gmail app passwords, any IMAP and SMTP mailbox; hosted mailboxes sit outside the cap

Mystrika

IMAP, SMTP and OAuth providers on its 2026 page; a 2024 help page needs a Gmail app password and calls Microsoft 365 setup complicated

The short answer

Connecting mailboxes, in one look.

Both connect over IMAP and SMTP. Warmerly adds one-click Microsoft sign-in, fills in Gmail's server settings for you and tests a mailbox before saving it. Mystrika's 2026 product page lists IMAP, SMTP and OAuth providers, while its help pages, written in 2024, describe an IMAP and SMTP form, app passwords, and a Microsoft 365 setup it calls much more complicated. Its help pages and our reading of them may be out of date. Last checked 22 October 2026.

Warmerly

Google and Microsoft sign-in, Gmail app passwords, any IMAP and SMTP mailbox; hosted mailboxes sit outside the cap

Mystrika

IMAP, SMTP and OAuth providers on its 2026 page; a 2024 help page needs a Gmail app password and calls Microsoft 365 setup complicated

The picture

Drawn side by side.

Connecting a mailbox, provider by provider

Pick a provider. Warmerly's steps come from its connection guide. Mystrika's come from its help articles, which the Internet Archive saved in 2024, and its 2026 Outreach page.

WarmerlyMystrika
Provider
WarmerlyFive steps in the guide
  1. Turn on 2-Step Verification on the Google account
  2. Create a 16-character app password at Google
  3. Choose Gmail or Google Workspace in Accounts, Add
  4. Enter the address and paste the app passwordServer settings fill in by themselves
  5. Connect: the connection is tested before it is saved

Each mailbox user needs their own app password. No Google sign-in button for mailboxes.

Mystrika2024 help article
  1. Enable IMAP in Gmail settings
  2. Enable 2-factor verification
  3. Create an app password
  4. Add Email ID, type G-Suite/Gmail, paste the app password
  5. Credentials are validated and the account is addedStats show up the next day

Optional sixth step: tie Google Authenticator to Mystrika for one-time codes.

WarmerlyFive steps in the guide
  1. Open Accounts and click Add
  2. Choose Microsoft 365 (work or school)
  3. Sign in with the address you want to connect
  4. Approve the permissions Warmerly asks for
  5. Connected: Warmerly never sees the password

Three usual causes if sending then fails: a different sign-in address, Authenticated SMTP off, or an alias without Send As.

Mystrika2026 page and 2024 article
  1. 2026: the Outreach page says IMAP, SMTP and OAuth providers are supportedIt does not name the providers
  2. 2024: setup is called much more complicated than a normal provider
  3. 2024: it involves PowerShell and multiple commands to enable IMAP and SMTP

We could not read a newer Microsoft 365 article, so the two sources are reported side by side.

WarmerlySame one-click sign-in
  1. Open Accounts and click Add
  2. Choose Outlook.com or Hotmail (personal)
  3. Sign in in the pop-up window
  4. Approve the permissions
  5. Connected, with one caveat for personal addresses

Microsoft switches SMTP sign-in off on many personal mailboxes, and Warmerly then says Microsoft is blocking sending.

Mystrika2024 help article
  1. Click Add Email ID and enter the name and address
  2. Choose the type IMAP / SMTP
  3. Host and port fill in automatically
  4. Enter the address and the login password for both IMAP and SMTP
  5. Credentials are validated and the account is added

The article says it is not a guide for professional Outlook or Office 365 addresses.

WarmerlyManual form
  1. Choose Another provider in the Add wizard
  2. SMTP host smtp.zoho.com, port 465
  3. IMAP host imap.zoho.com, port 993
  4. Tick the box if the IMAP login differs from the SMTP login
  5. Connect: tested before it is saved
Mystrika2024 help article
  1. Allow IMAP and SMTP on the Zoho plan firstFree Zoho plans do not have them
  2. With 2FA on, create a Zoho app password
  3. Add Email ID, type IMAP / SMTP
  4. Host and port are a best guess, so check the regionUK and EU: imappro.zoho.eu. USA: imappro.zoho.com
  5. Credentials are validated and the account is added
WarmerlyManual form
  1. Choose Another provider in the Add wizard
  2. Look up your provider's SMTP and IMAP host and port
  3. Enter both pairs, and the login for each
  4. Connect: the test shows the exact server response if it fails

Test connection in the mailbox menu shows the plain-language reason and the raw SMTP code.

Mystrika2024 help article and tools page
  1. Test the same settings in an email client such as Thunderbird first
  2. Add Email ID, type IMAP / SMTP
  3. Enter address, password, server, port and encryption
  4. Or try the free credential test page before adding it

Its article says there is almost no point contacting support if the email client check fails.

A step list is not a stopwatch. How long a connection takes depends on the provider's own security screens.

How Warmerly does it

Warmerly, in detail.

Three ways in: one-click sign-in for Outlook.com, Hotmail and Microsoft 365, a Gmail app password with the settings pre-filled, and a manual form for any other IMAP and SMTP provider. A mailbox is tested before it is saved, and a connected mailbox counts against the plan's mailbox limit.

01

One-click sign-in for Microsoft

Outlook.com, Hotmail and Microsoft 365 mailboxes connect through a sign-in window. You approve the permissions, Microsoft hands Warmerly a permission slip, and Warmerly never sees or stores the password. If the sign-in does not finish, the guide's fallback is manual setup with an app password.

Warmerly product, checked 22 October 2026

02

Gmail and Workspace use an app password

Gmail and Google Workspace connect with a 16-character Google app password, created after 2-Step Verification is on. Warmerly fills in the server settings, so you enter the address and paste one password. There is no Google sign-in button for mailboxes. Each mailbox user needs their own app password, and Google's domain-wide delegation, which would connect a whole Workspace in one step, is not supported.

Warmerly product, checked 22 October 2026

03

Any other provider through a form

Zoho Mail, Namecheap Private Email and any other provider connect by typing the SMTP and IMAP host and port. The guide lists Zoho (smtp.zoho.com 465, imap.zoho.com 993) and Namecheap Private Email (mail.privateemail.com 465 and 993). A checkbox lets the IMAP login differ from the SMTP login for providers that issue a separate reading password.

Warmerly product, checked 22 October 2026

04

Tested before it is saved

The Connect button tests the connection first and saves the mailbox only if the test works. Two API calls, detect and test-connection, let you check settings before connecting, and a Test connection item in the mailbox menu shows the plain-language reason and the raw server response, including the exact SMTP code.

Warmerly product, checked 22 October 2026

05

The Microsoft failures it explains

The guide names three usual causes when Microsoft says a connection worked but sending fails with 535 5.7.3: a sign-in address that differs from the mailbox's primary SMTP address, Authenticated SMTP switched off (off by default on tenants created since 2020), and sending from an alias or shared mailbox without Send As or Full Access. It also says personal Hotmail and Outlook.com addresses often have SMTP sign-in switched off by Microsoft, even after a successful one-click connect.

Warmerly product, checked 22 October 2026

06

Connecting many at once

An API call connects several mailboxes in one request. The limit is all-or-nothing: if the batch would pass the plan's mailbox limit the whole request is refused with a 402, and past that gate each row is inserted on its own, so one bad row does not lose the others. Hosts that point at private or internal addresses refuse the whole batch.

Warmerly product, checked 22 October 2026

07

What a connected mailbox counts against

A connected mailbox counts against the plan limit: 1 on Free, 5 on Starter, 25 on Growth and 100 on Agency. Hosted mailboxes, where Warmerly runs the mailbox on its own mail servers and sets up the domain's DNS, sit outside that count and are not Google Workspace or Microsoft 365.

Warmerly product, checked 22 October 2026

08

When a login stops working

A login failure during sync or warmup counts against the mailbox. At 3 consecutive authentication failures the mailbox is paused, flagged as needing a reconnect, and the owner gets a Reconnect needed alert. Passwords and OAuth tokens are encrypted at rest and never returned by the API.

Warmerly product, checked 22 October 2026

How Mystrika does it

Mystrika, in detail.

Mystrika's current product page says it supports standard IMAP, SMTP and OAuth providers. Its help centre, in the copies we could read, dates from 2024 and describes an Add Email ID form: IMAP and SMTP with an app password for Gmail, Zoho and iCloud, a login password for Outlook.com, and a PowerShell-based setup for Microsoft 365. It also publishes a free credential test tool.

01

IMAP, SMTP and OAuth on the 2026 page

In its FAQ, the Outreach product page answers 'Can I use my existing email accounts?' with 'Yes. Mystrika supports standard IMAP, SMTP and OAuth providers.' It does not say which providers use OAuth.

web.archive.org/web/20260710212841/https://mystrika.com/products/outreach · read 2026-10-22 (Internet Archive copy of 2026-07-10)

02

Gmail: three steps with an app password (2024)

The 2024 help article for G-Suite and Gmail lists three steps: enable IMAP, enable 2-factor verification, create an app password. In the Add Email ID form you pick the type G-Suite/Gmail and paste the app password, and it says the system validates the credentials and adds the account. 'Stats will show up next day.' An optional step ties Google Authenticator to Mystrika so it can generate one-time codes.

web.archive.org/web/20240615092552/https://mystrika.com/knowledge-base/article/add-email-address-from-gsuite-gmail · read 2026-10-22 (Internet Archive copy of 2024-06-15)

03

Outlook.com: IMAP and SMTP with a login password (2024)

A 2024 article for outlook.com and hotmail.com addresses says to choose the type IMAP / SMTP, let the system fill in host and port, and enter the email address and the login password for both IMAP and SMTP. It states that it is not a guide for professional Outlook or Office 365 addresses.

web.archive.org/web/20240422152300/https://mystrika.com/knowledge-base/article/add-email-address-from-outlook · read 2026-10-22 (Internet Archive copy of 2024-04-22)

04

Microsoft 365: described as complicated (2024)

The 2024 IMAP troubleshooting article says setup for Microsoft or Outlook servers is 'much more complicated than a normal email provider' and involves handling PowerShell and running multiple commands to enable IMAP and SMTP. It links a guide, but the link in the copy we read is a placeholder.

web.archive.org/web/20240223070001/https://mystrika.com/knowledge-base/article/add-email-imap-issue · read 2026-10-22 (Internet Archive copy of 2024-02-23)

05

Zoho and iCloud (2024)

The Zoho article says IMAP and SMTP must be allowed on the Zoho plan, and that free Zoho plans do not have them. With 2FA on, Zoho requires an app password. The IMAP article lists regional hosts: imappro.zoho.eu and smtppro.zoho.eu for UK and EU servers, imappro.zoho.com and smtppro.zoho.com for USA. The iCloud article uses an app password in the same form.

web.archive.org/web/20240422170118/https://mystrika.com/knowledge-base/article/add-email-address-from-zoho · read 2026-10-22 (Internet Archive copy of 2024-04-22)

06

Check it in an email client first (2024)

Its IMAP failure article says 95% of the time an error comes from the configuration, asks you to test the settings in a client such as Thunderbird, and says there is 'almost no point' contacting support if that check fails. It notes that a client pop-up switches the sign-in to OAuth, whereas Mystrika requires IMAP and SMTP settings that work without one.

web.archive.org/web/20240223070001/https://mystrika.com/knowledge-base/article/add-email-imap-issue · read 2026-10-22 (Internet Archive copy of 2024-02-23)

08

Mailboxes can arrive from a partner as a CSV

Its Email Accounts page, written about the partner DoYouMail, says you download a CSV of accounts from the partner and upload it into Mystrika, then warm them. The page says standard IMAP and SMTP support keeps those accounts compatible with Mystrika.

web.archive.org/web/20260710204550/https://mystrika.com/products/email-accounts · read 2026-10-22 (Internet Archive copy of 2026-07-10)

What Mystrika does not say

We looked, and found no statement on these. That is about its published pages only, not about the product.

  • Which providers connect with OAuth, and whether Google or Microsoft sign-in buttons exist today
  • A 2026 version of the Gmail, Outlook and Microsoft 365 help articles; the ones we could read are dated 2024
  • Whether the Microsoft 365 PowerShell steps from 2024 still apply, or whether the 2026 OAuth wording replaced them
  • A bulk import of mailboxes other than the partner CSV described on the Email Accounts page
  • What happens after repeated login failures: whether a mailbox is paused, and whether the owner is alerted
  • Whether a connection is tested for sending and reading before it is saved, beyond the sentence that credentials are validated
  • How passwords and tokens are stored
  • A limit on how many mailboxes can be added on a paid plan, other than the 2024 soft limit of 199 email ids for warmup

Where the sources disagree

We report each version rather than pick one.

  • Mystrika's 2026 Outreach page says it supports 'standard IMAP, SMTP and OAuth providers'. Its 2024 help articles describe IMAP and SMTP with app passwords or login passwords, and call Microsoft 365 setup a PowerShell job. We report both and cannot tell which is current.
  • The 2024 Outlook.com article says to enter your login password for IMAP and SMTP. Gmail, Zoho and iCloud articles from the same period use app passwords. We do not know whether the login-password route still works with Microsoft today.
  • The 2024 pricing and help pages gave a soft limit of 199 email ids for warmup. The 2026 home page says up to 50 senders on Free Forever and unlimited senders on paid plans.
The numbers

Only what we could verify.

Connecting mailboxes: Warmerly and Mystrika side by side. Warmerly is in the first column.
MeasureWarmerlyMystrika
Connecting mailboxesGoogle and Microsoft sign-in, Gmail app passwords, any IMAP and SMTP mailbox; hosted mailboxes sit outside the capIMAP, SMTP and OAuth providers on its 2026 page; a 2024 help page needs a Gmail app password and calls Microsoft 365 setup complicated
Microsoft 365One-click sign-inOAuth providers listed in 2026; a 2024 article describes a PowerShell setup
Gmail and WorkspaceApp password, settings pre-filledApp password with IMAP and 2FA steps (2024)
Outlook.com and HotmailOne-click sign-inIMAP and SMTP with the login password (2024)
Test before savingYes, and a Test connection menu itemCredentials validated when added; a separate credential test page
Failed logins before a pause3 in a rowNot stated
Mailbox cap on the plan1 on Free, 5 on Starter, 25 on Growth, 100 on AgencyUp to 50 senders on Free, unlimited on paid plans
In practice

What it means for you.

Our reading of the facts above. Not a promise, and not the only reasonable reading.

1

Connecting Gmail takes the same three steps in both

Whichever tool you use, a Gmail or Workspace mailbox needs 2-Step Verification, an app password and IMAP switched on. On Workspace, an admin may have to allow 2-Step Verification first, and the page that creates app passwords can say the setting is not available. Warmerly's guide walks through the admin console path. Mystrika's 2024 article does not cover that case.

2

Microsoft is where the two differ most

Warmerly offers one sign-in for Microsoft 365 and Outlook.com. Mystrika's 2026 page says OAuth providers work, but the only Microsoft help we could read, from 2024, describes a PowerShell setup. If most of your mailboxes are Microsoft 365, test one in each tool before you move many.

3

Do the email client check either way

Mystrika's advice to test the settings in Thunderbird first is sound for any tool. If a mailbox cannot sign in with the same server, port and password in a desktop client, no warmup tool will connect it. Warmerly's Test connection shows the raw server response, which tells you the same thing without leaving the app.

4

Know what counts against the limit

On Warmerly each connected mailbox counts: 5 on Starter, 25 on Growth, 100 on Agency. If you plan to connect 40 mailboxes, Growth stops at 25 and Agency covers up to 100. Mystrika's paid plans list unlimited senders, so connection count is not the limit there; prospect slots are.

5

Moving a mailbox between the two

The mailbox keeps its reputation with Gmail or Microsoft, so reconnecting it elsewhere does not reset it. Turn warmup off in one tool before turning it on in the other, so only one pool writes warmup mail from it. Then connect it with the method for its provider.

6

Ask for the 2026 article before you rely on the 2024 one

Mystrika's help articles we read are from 2024 snapshots. If you are deciding on the strength of a connection step, ask its support whether the article still matches the product, and keep the date of the answer.

Who it suits

Pick the one that fits.

Warmerly

Warmerly is the better fit if

  • Most of your mailboxes are Microsoft 365, Outlook.com or Hotmail and you want a sign-in rather than a server form
  • You want a connection tested before it is saved and an exact error when it fails
  • You want a paused mailbox and an alert after 3 failed logins rather than silent retries
  • You want hosted mailboxes outside the plan cap, set up with their DNS
Mystrika

Mystrika is the better fit if

  • You connect many Gmail, Zoho or iCloud mailboxes by app password and are happy with an IMAP and SMTP form
  • You buy mailboxes from the partner it names and import them as a CSV
  • You want a public credential test page that checks IMAP and SMTP settings before you add a mailbox
  • You want the option to tie Google Authenticator to a Gmail mailbox for one-time codes
Questions
How do I connect a mailbox to Mystrika?

Its help articles, saved by the Internet Archive in 2024, describe clicking Add Email ID, entering the name and address, choosing a type (G-Suite/Gmail or IMAP / SMTP) and pasting an app password or login password. The system validates the credentials and adds the account. Its 2026 Outreach page says IMAP, SMTP and OAuth providers are supported.

Does Mystrika support Microsoft 365?

Its 2026 page lists OAuth providers without naming them. A 2024 help article calls Microsoft and Outlook setup much more complicated than a normal provider and says it involves PowerShell. We could not read a newer article, so test one mailbox before you move many.

How does Warmerly connect Gmail?

With a Google app password. You turn on 2-Step Verification, create the app password, choose Gmail or Google Workspace in the Add wizard, enter the address and paste the password. Warmerly fills in the server settings and tests the connection before saving.

What if Microsoft says the connection worked but sending fails?

The usual causes are a sign-in address that differs from the mailbox's primary SMTP address, Authenticated SMTP switched off for the tenant or the user, or sending from an alias or shared mailbox without Send As or Full Access. Warmerly's Test connection shows the exact SMTP code.

Sources

Mystrika pages were read on 22 October 2026. Plans and wording change, so check the vendor's own page before you decide. Warmerly details come from the product as it runs today.

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