Overcome Outlook sign on issues while attmpting to while introducing Yahoo email

Question

Through our 365 Microsoft account we have used Outlook (Not Classic) with Comcast email. Comcast has turned their email business over to Yahoo. As we attempt to utilize Outlook with Yahoo mail on our Windows 11 Lenovo laptop we experience a problem.

We have completed the steps to convert to Yahoo. Email is accessible if we go to Yahoo mail and access the email that way. However we would like to use Outlook.

When I click on Outlook I receive a sign-on window. I enter the Yahoo password and receive a notice that sign on has failed. Problem repeats. All info read says we need to sign on with Yahoo password. Have attempted to use Microsoft password. Same result. I'm stuck.

Answer 1

Comcast Migration to Yahoo

Classic Outlook - Adding a Comcast account that has been migrated to Yahoo
See the Answer by "Hornblower409 Apr 16, 2026" in
https://learn.microsoft.com/en-us/answers/questions/5663018/outlook-wont-let-me-sign-into-my-imap-server

New Outlook - Adding a Comcast account that has been migrated to Yahoo
See the Answer by "Hornblower409 Apr 23, 2026" in
https://learn.microsoft.com/en-us/answers/questions/5868248/email-sync-error-on-new-comcast-email-account

Answer 2

To use the new Outlook for Windows with a Yahoo (Comcast-migrated) account, the account must be added using Yahoo’s OAuth sign-in flow, not just by typing the password into a generic sign-in box.

Follow these steps in new Outlook for Windows:

1. Open Outlook.
2. Go to the View tab and select View settings, or go to the File tab and select Account info.
3. Select Accounts > Your accounts.
4. Select Add Account.
5. Enter the full Yahoo email address (the one Comcast migrated to Yahoo) and select Continue.
6. On the Sync your Yahoo account screen, select Continue.
7. A browser window opens to Yahoo sign-in:
   • Enter the Yahoo email address and Yahoo password.
   • Complete any two-factor authentication prompts if configured.
8. When the Yahoo account permissions window appears, select Agree to allow Outlook access via Yahoo OpenID/OAuth.
9. When the browser shows a prompt like https://outlook.office.com wants to open this application, select Open.
10. Return to Outlook and select the Yahoo account’s Inbox to confirm messages are syncing.

If the sign-in window you see is not launching a browser or showing the Yahoo permissions/Agree screen, remove any partially added Yahoo account from Outlook first, then repeat the steps above so Outlook can start a fresh OAuth-based connection.

If problems persist, switching from classic Outlook to the new Outlook for Windows and then adding the Yahoo account there has been a successful workaround for similar Yahoo sign-in issues.

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References:

• Add or manage a Yahoo! email account in Outlook
• Troubleshoot Outlook email setup
• Yahoo Account No Longer Syncing to Outlook - Microsoft Q&A