Issue with Mail application on new Macbook Pro M3 Pro

I fixed this by changing my default browser to Chrome temporarily. Seems to be an issue with Safari which is what is being used to login via browser.

This was the fix to my problem.

Safari on the M3 was not able to get through to allow permissions and produce a 404 each time I got to the point of accepting permissions. I setup the default browser to Chrome to add the account and then switched it back.

Thank you so much @benjackson77!

This is a new Safari issue. I have been able to fix this by setting either Firefox or Chrome as the default browser for this setup. Once you are successful, you can reset your default browser.

Apple - please fix this bug with Safari.

Brandon_Needs_You wrote:

I have been trying to log into my personal gmail account and am unable to log in. The account is information is correct and even sends me a notification to my phone showing that the account has been accessed and asking me to grant permission. I select yes and then the screen hangs for a few the I get a google error message that reads:

400. That’s an error.

The server cannot process the request because it is malformed. It should not be retried. That’s all we know.

I dont have any issues on my ipad logging into my email account just my Mac.

Mail|>Settings>Accounts>Server settings

I would verify your settings here, turn off automatic and take a look, make changes if necessary.

Connection Doctor may have some info >Show Details

Use Connection Doctor in Mail on Mac - Apple Support

I have this issue and every answer is to "upgrade your mac os" well, me and this poster have BRAND NEW MACS they are up to date. This is an issue with Apple and Google mismatch in security Auth and telling users to "update" or follow out of date instructions to work around this is not a helpful answer. Has anyone with an actual new Sonoma Mac using a standard gmail account that has worked for over a decade on every iOS and MacOS device is now broken.

I'm having the same issue. I also have a new M3 MacBook.

I've tried multiple different second factor authentication methods as well as safe mode to no success.

This all seemed to stop working after the password change a week ago.

iOS doesn't seem affected by the problem as my iPhone just took the new password for the google account and has been working per usual.

Has anyone else been successful re-adding their google account on MacOS? If so does the safe mode process work or have you used something else?

Thank you.

See my suggestion in this thread for an alternative solution. It appears Safari's “advanced tracking protection” may be the culprit.

This fixed it for me. THANK YOU. My company's tech support could not figure it out. Thank goodness I did my own research. ARGH.

Worked for me! I deleted a passkey in a password manager and got hung up in that vicious loop. The chrome fix worked!

Thank you!! I've been dealing with this for an hour and half. FinallY!

Temporary change to chrome browser let me add mail account.

Wonder if this occurred with latest MAC update a few days prior- hopefully apple will update with bug fix!