What to do when Error Code 700 is showing and emails are not being sent?

Hi everyone,

I’m currently experiencing the same issue across all of my devices where Gmail has stopped syncing in Outlook 365. This affects:

• Outlook on Windows 11

Outlook on MacBook Pro

Outlook on iPhone (iOS)

Nothing has changed on my side — all systems are fully updated, and no settings were recently modified. Gmail still works perfectly fine when accessed via the web browser.

What I’ve already tried:

Removed and re-added the Gmail account

Tried with app-specific passwords (with 2FA enabled)

Attempted both standard and manual IMAP setup

Ensured all updates are current on every platform

Unfortunately, the issue persists on all devices.

Initial Analysis:

This appears to be an issue with Outlook failing to authenticate Gmail properly — possibly due to recent changes in how Google handles OAuth or app access. Based on what I’m seeing, this is not a local configuration issue but something that affects multiple users and platforms.

Temporary Workarounds (not ideal, but functional):

Use Gmail directly via the browser

Try generating an app-specific password and use manual IMAP setup in Outlook

For business accounts, check Google Workspace settings for app access restrictions

Request:

This needs urgent attention from Microsoft and Google. It’s clearly affecting many users, and a coordinated solution is needed. If anyone has more information or a long-term fix, please share here.

Thanks, MartinHi everyone,

I’m currently experiencing the same issue across all of my devices where Gmail has stopped syncing in Outlook 365. This affects:

Outlook on Windows 11

Outlook on MacBook Pro

Outlook on iPhone (iOS)

Nothing has changed on my side — all systems are fully updated, and no settings were recently modified. Gmail still works perfectly fine when accessed via the web browser.

What I’ve already tried:

Removed and re-added the Gmail account

Tried with app-specific passwords (with 2FA enabled)

Attempted both standard and manual IMAP setup

Ensured all updates are current on every platform

Unfortunately, the issue persists on all devices.

Initial Analysis:

This appears to be an issue with Outlook failing to authenticate Gmail properly — possibly due to recent changes in how Google handles OAuth or app access. Based on what I’m seeing, this is not a local configuration issue but something that affects multiple users and platforms.

Temporary Workarounds (not ideal, but functional):

Use Gmail directly via the browser

Try generating an app-specific password and use manual IMAP setup in Outlook

For business accounts, check Google Workspace settings for app access restrictions

Request:

This needs urgent attention from Microsoft and Google. It’s clearly affecting many users, and a coordinated solution is needed. If anyone has more information or a long-term fix, please share here.

Thanks,
Martin

Same problem here. No config changes, but Gmail account produces above error. Please provide a fix asap, this shines a bad light on the otherwise great product.

Hi,

Since I didn't see an answer yet. I've experienced the same problem.

Had to do a full setup of my account again.

For me it had to do with a different way of filling in my domain.

Normally I had to use a foreslash (Ex. DOMAIN\ ). That doens't work anymore.

You only have to fill in your domain without using any slash ( Ex. DOMAIN ).

Good luck!

I am experiencing the same problem for the last 24 hours with the Outlook client on a Samsung S23+. Outlook on Windows 10 for the same account is working and syncing with gmail just fine.

I have signed out and in again and no change.

In the last hour, there has been some catch up, but it's not complete - there's a time lag.
It looks like it's either an M365 or gmail cloud issue. Someone's changed something and it has a bug....

I ended up deleting my gmail account in Outlook and then adding it back in. That has seemed to work for me thus far.