No authentification tab

I have 2 accounts. 1 of them has no authentification tab. This one shows a red triangle and does not work at all (no communication).
What can I do about it?

If there is no authentication section, then the account is setup as oAuth.

If this is an or other Microsoft account, please see this topic which is discussing the issue with Microsoft.

I have also given a manual setup in my comments there that will enable you to setup the account without oAuth, and bypass Microsoft’s issue.

I have been using this account for more then a year and suddenly this account does not work anymore.
How is that possible when this is a problem with Microsoft?

It means if your are connecting to a Microsoft account and it is not authenticating with oAuth, that Microsoft changed something on their server a few days back.

Does that mean that I can better chose another server and change my e-Mail adress?
That affects al of my eMail contacts.

If the accounts are with, please see the topic I referred to above. I gave instructions there of how to setup your account without oAuth, and if you do that, it will work.

If the accounts are not with, who is the email provider?

I had the same problem after last Microsoft update to drop password and using a smart phone authentication app instead. They disabled old password so that account now must be authenticated thru their app. I did make em client to work with doing following. 1.delete @outlook account from em client. 2. Start to setup new email account type as other. 3. Manually setup Imap and smtp server credentials using new password generated by authenticator app on smart phone. Imap port 993, smtp port 587. It is working now without problem.