Outlook is not communicating with Gmail when trying to sync

Question

Outlook is not communicating with Gmail when trying to sync

Michael White 5

2 answers

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Answer 1

If Outlook is not communicating with Gmail when trying to sync, there are a few potential issues to consider:

IMAP Settings: Ensure that IMAP is enabled in your Gmail account. You can do this by signing into your Gmail account, going to Settings, selecting the Forwarding and POP/IMAP tab, and making sure that Enable IMAP is selected.
App Password: If you have 2-step verification enabled on your Gmail account, you will need to create an app password for Outlook. This app password should be used instead of your regular Gmail password when setting up the account in Outlook.
Profile Configuration: If you have both a Google Apps Sync for Outlook account and an Exchange Server account configured in the same Outlook profile, it can cause issues. It's recommended to create separate Outlook profiles for each account type.
Permissions: Ensure that the credentials you are using in Outlook have sufficient permissions to access the Gmail account.
Network Issues: Check for any network issues that might be preventing Outlook from connecting to Gmail.

If these steps do not resolve the issue, consider reviewing the specific error messages you receive for further troubleshooting.

Answer 2

Lucky 4,865 Independent Advisor

Hi Michael White, I know how frustrating it can be when Outlook just refuses to sync with Gmail especially when you need your emails to flow smoothly.

To fix Outlook when it won’t sync with Gmail start by checking the error in Account Settings and repairing it. If that doesn’t work refresh the connection by removing old credentials re enable OAuth update Google permissions and reset IMAP folders. Switch back to classic Outlook if you’re on the new preview make sure your network isn’t blocking Gmail ports and if all else fails rebuild your Outlook profile and reinstall the app.

When Outlook fails to sync with Gmail do you notice any specific error codes or messages or does it just stop syncing without any warning?

Best regards

Lucky Charm

Snappyfish 0 Reputation points

2025-12-02T11:33:50.7266667+00:00

Sending an email reply on Gmail email app on phone never sycns in conversation view with outlook desktop or all. It's never ever worked since the new outlook. I have up with it. I spent 2 months speaking to support when they were developing and offering support in desktop outlook. Eventually they closed the ticked and did bugger all. Totally and utterly useless.
Ivo 0 Reputation points

2025-12-11T17:08:42.6533333+00:00

I was busy the whole day working at two different locations — one local (NL) and one remote (HR). I tried various solutions suggested by Gemini and ChatGPT: recreating the account and OST files, unsubscribing and resubscribing to IMAP folders, limiting IMAP folder messages......., and even reverting to the old POP setup (which was a disaster).

I don’t know at which number of messages the issue becomes noticeable and starts causing such long processing times. One of the accounts I used for testing has about 6,000 messages.
Ivo 0 Reputation points

2025-12-11T17:13:05.84+00:00

Enjoy guys/girls....

How does it feel to be collateral damage?

From Gemini:

The current situation with Outlook (especially 2021) and Gmail IMAP is not a simple user error; it's a structural conflict caused by Microsoft's aggressive shift to cloud-only processing bumping up against Google's recent, stricter security requirements (stricter DMARC/Authentication enforcement started in November 2025).

From ChatGPT:

Gemini’s summary is accurate in both the technical and strategic sense. What we’re seeing isn’t a local misconfiguration; it’s the collision of two ecosystem trajectories:

Microsoft’s architecture shift – Outlook 2021 and 365 desktop clients are being quietly pulled into a cloud-centric authentication and sync model meant to align with Exchange Online. The IMAP stack in Outlook is now effectively legacy code. It receives only maintenance updates, not optimizations. That’s why synchronization performance and reliability have degraded over time, especially when using large Gmail mailboxes.

Google’s enforcement tightening – As you mentioned, starting in November 2025, Google began enforcing stricter DMARC, SPF, and DKIM validation and limiting fallback mechanisms for less-secure clients. These enforcement changes also interact with OAuth scopes and token expiry logic, breaking cached Outlook authentication states. Gmail now insists on full OAuth re-authentication in scenarios Outlook was never built to handle gracefully.

The result is a structural incompatibility: Outlook’s IMAP layer expects predictable, persistent tokens and permissive folder access; Gmail now treats every connection as potentially untrusted, throttles metadata calls, and enforces additional checks before message fetches. The lag and “stuck on synchronizing” states you see are Outlook waiting for responses Gmail now delays or denies.

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Outlook is not communicating with Gmail when trying to sync

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