Outlook synch issues (classic) - add gmail issues (new)

Question

I have spent 2 days (I was IT so refused to give say uncle) but ....UNCLE.

Have tried to switch to new a few times and went back as it was not ready for prime time.

A few days ago, synch would never send a new email and it stayed in outbox. I did everything I could find as a suggested fix and no luck. I tried to take it to a shop and they said that there are many issues like that that just crop up and they recommended just stay on google.com for gmail.

I then tried the new one again. It brought in new emails only but nothing from google.com

I don't know what is going on with outlook developers but I will say, they are failing miserably to produce a product (new), fix a product (old). GARBAGE...

Answer 1

The sync and Gmail add issues match known problems with Gmail accounts in classic Outlook and sign-in problems in both classic and new Outlook. There are two main things to check and then two different fixes depending on which Outlook experience is used.

1. Confirm Outlook build and Gmail IMAP status

• In classic Outlook, go to File → Office Account → About Outlook and confirm the channel/build.
• For Gmail, ensure IMAP is enabled as described in Google’s "Add Gmail to another email client" guidance (linked from the article below). If IMAP is disabled, Outlook will fail with errors like “We weren’t able to set up your Google account with IMAP. You may need to make changes to your Gmail settings.”

2. Fix classic Outlook not syncing Gmail (messages stuck in Outbox / cannot connect) Classic Outlook has a specific issue when the Gmail consent box is not granted correctly during browser sign-in. Symptoms include:

• Errors such as:
  • "We couldn't log on to the incoming (POP/IMAP) server. Please check your email address and password and try again."
  • "We weren’t able to set up your Google account with IMAP. You may need to make changes to your Gmail settings."
  • Send/Receive error 0x800CCC0E and failure to sync folders.

Cause:

• When the Gmail account was added, the browser sign-in screen’s permission box was not checked for:
  • "Read, compose, send, and permanently delete all your email from Gmail" under Microsoft apps & services can access.

Resolution (fixed builds – Retry solution):

• Ensure classic Outlook is updated to at least Current Channel Version 2412 Build 18324.20168.
• When the Gmail error dialog appears in Outlook, use the Retry link.
• This re-opens the browser sign-in. During sign-in, explicitly check the box allowing Microsoft apps & services to "Read, compose, send, and permanently delete all your email from Gmail."
• Complete sign-in; Outlook should then be able to sync and send (Outbox should clear once the connection is restored).

If on the fixed build but Retry does not work:

• Use the manual workaround described in the same article:
  • Remove the problematic Gmail credentials and related identity entries (per the registry/Credential Manager guidance in the article’s Manual Workaround section).
  • Re-open Outlook and use Sign in via browser from the business bar for the affected profile, again ensuring the Microsoft apps & services permission box is checked.
  • If the Gmail account was removed from the profile, use File → Add account to add it back and complete browser sign-in with the correct permission.

3. Fix “browser or app may not be secure” / IMAP setup failures when adding Gmail When adding Gmail to classic Outlook (or re-adding after problems), the following errors can appear:

• “The browser or app may not be secure.”
• “We weren’t able to set up your Google account with IMAP. You may need to make changes to your Gmail settings.”

Known resolution:

• Outlook has shipped a fix that changes sign-in to open another browser window. This fix is available in:
  • Beta Channel: Version 2404 (Build 17531.10000)
  • Current Channel Preview: Version 2404 (Build 17531.10000)
  • Current Channel: Version 2404 (Build 17531.10000)
  • Monthly Enterprise Channel: Version 2407 (Build 17727.10000)
  • Semi-Annual Enterprise Channel (Preview) and Semi-Annual Enterprise Channel: TBD

Action:

• Update Office/Outlook to one of the fixed builds listed above.
• If previously switched to an Insider channel as a workaround, use the same documented steps to switch back to Current Channel after updating.
• After updating, add the Gmail account again; sign-in should now complete in the external browser window.

4. New Outlook only showing new mail New Outlook uses a different architecture and account model than classic Outlook. If only new mail appears and older Gmail content is missing, that typically indicates:

• The account connection is only partially established or limited to server-side content from the time of connection.
• Historical mail that was previously cached only in classic Outlook’s local data file will not automatically appear in new Outlook.

Given the need for full Gmail history and reliable sync, the recommended path in this scenario is:

• Use classic Outlook with the fixed builds and Gmail sign-in fixes above.
• Ensure the Gmail account is re-added and fully re-authorized via the browser with the correct permissions.

If problems persist after updating and re-authorizing:

• Remove the Gmail account from the classic Outlook profile.
• Create a fresh Outlook profile and add the Gmail account again, completing the browser sign-in with the required Microsoft apps & services permission.

These steps align with the current documented fixes for Gmail sign-in and sync issues in classic Outlook and should restore reliable send/receive behavior without relying solely on the web Gmail interface.

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References:

• Unable to add a Gmail account to classic Outlook
• Unable to sign in or add a Gmail account to classic Outlook