Getting 2400 error in outlook application

Try to delete email account in control panel. Then add it again.
I set a PIN of this account from other computer, thus might get an authorization problem.

same here as of 06/19/2023. I have had the 2FA for a few weeks now and this happened this morning on my work PC. End the end I removed the account (hotmail). Closed and restarted Outlook. Add New Account and readded the hotmail account. It error coded on the password, however when I selected the 2FA option, I clicked the number sent to my cell phone that matched outlook screen and it worked like a charm.

Crises over.

I have the same issue with the Preview of the new Outlook App for Windows 11.

As it is a preview, I am not too mad about it, but happy if there is a solution to it.

I suspect a mixup between my private microsoft account and my work email account (which runs with the same email-address)

The account does work normally in the "old" Outlook App

Since yesterday, June 17th, 2023, I cannot open Outlook without getting the "ERROR, something went wrong [2400]" message.... won't accept my password, and won't open Outlook. The Outlook webpage can work well.

Other MS Suite opened perfectly.

Please let me know how to fix this?

Thank you for taking the time to post this fix, it worked for me as well.

This error started occurring for me yesterday, I'm happy I managed to fix it.

Kudos to you.