How can I fix my Outlook 365 not receiving gmail. It was working but it stopped all of a sudden

Hi @Aby Paul, 

Thank you for taking the time to describe what changed and confirm that this started suddenly after previously working. 

Based on the details you shared, classic Outlook for Microsoft 365 has stopped receiving mail for one of your Gmail accounts even though the other Gmail account is still syncing normally. 

This behavior usually happens when Outlook is no longer syncing with the mail server due to a connection interruption, an account credential or authorization change, or a local Outlook setting that prevents it from checking for new mail.  In many cases, Outlook is either stuck in a background process, set to work offline, or holding outdated cached data, which can make the Inbox appear “up to date” while it is not pulling new messages.  Below are a few targeted checks typically restore the sync for the affected account.  

1/ Fully restart Outlook and confirm it is working online, then force a manual sync 

• Close Outlook completely. 
• Open Task Manager (Ctrl + Shift + Esc) and end any remaining Outlook processes, then reopen Outlook. 
• In Outlook, open the Send/Receive tab and make sure Work Offline is not enabled (the status bar should not show “Working Offline”). 
• Select Send/Receive All Folders (or select Update Folder for the current mailbox folder) to force a fresh sync and pull in the latest mail. 

2/ Repair the affected Gmail account connection inside Outlook (IMAP accounts) 

• In Classic Outlook, go to File, then Account Settings, then Account Settings. 
• Select the Gmail account that is not updating, then select Repair and follow the on screen prompts. 
• After the repair completes, restart Outlook and test Send/Receive again to confirm new messages arrive. 
• If you recently changed the Gmail password, update the stored password when prompted and then restart Outlook to re-establish the connection.  
• Reference: Unable to add a Gmail account to classic Outlook - Microsoft Support 

3/ Eliminate local Outlook blockers (add-ins, cache, and profile) 

• Start by disabling non-essential COM add-ins: File, Options, Add-ins, set Manage to COM Add-ins, select Go, then uncheck add-ins that are not required and restart Outlook. 
• If the Inbox still does not update, clear the Outlook cache to force Outlook to download fresh data from the server again. 
• If the problem remains isolated to that one Gmail account, create a fresh Outlook profile and add the Gmail account there to rule out profile-level corruption. 

For your reference that you can concern: Outlook not receiving emails: Fixing Inbox not updating issues 

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I hope this response has helped address your question and clarify the behavior you're experiencing. Please feel free to reply if you have any further questions, I would be happy to assist further.   

Thank you for your patience and your understanding. I look forward to continuing the conversation.  

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Follow these steps focusing on the one Gmail account that stopped working, since the other one proves Outlook and the network are generally OK:

1. Confirm Gmail IMAP is enabled for that account The broken Gmail account may have IMAP disabled.
   1. In a browser, sign in to the problem Gmail account at Gmail.com.
   2. Select Settings (gear icon) > See all settings.
   3. Go to the Forwarding and POP/IMAP tab.
   4. Under IMAP access, make sure Enable IMAP is selected.
   5. Select Save Changes.
2. Verify server settings in Outlook for that Gmail account If IMAP is enabled, verify Outlook is using the correct Gmail IMAP/SMTP settings for the failing account:
   • Incoming mail (IMAP) server: imap.gmail.com, SSL required, Port 993
   • Outgoing mail (SMTP) server: smtp.gmail.com, SSL required, TLS required if available
     • Port for SSL: 465
     • Port for TLS/STARTTLS: 587
   • Account name/username: full Gmail address of the failing account
   • Password: the correct Gmail password (or app password if configured)
3. Re‑add the failing Gmail account in Outlook (if needed) If the account still does not receive mail after steps 1–2, remove only the failing Gmail account from Outlook and add it again using the correct IMAP/SMTP settings above.
4. Update Outlook to a build that includes recent Gmail fixes Problems adding or syncing Gmail can be caused by older Outlook builds or authentication changes.
   • Make sure Outlook for Microsoft 365 is updated to a build that includes the Gmail sign‑in fixes described in the classic Outlook article (for example, Version 2404 Build 17531.10000 or later in the listed channels).
   • After updating, restart Outlook and test the failing Gmail account again.

If the failing Gmail account still will not sync after these steps, repeat the IMAP‑enable check in Gmail for that specific account and confirm that only that account’s settings differ from the Gmail account that is working.

References:

• Fix problems connecting your Google account to the Microsoft Cloud
• Unable to sign in or add a Gmail account to classic Outlook