Unable to remove mail or internet accounts on Mac

I’ll tel you what’s up - lack of information from you. More if it would be nice. For example: what device(s) are we talking about, phone, tablet, computer, all? Is it your device? Was it purchased by you new from a reputable source? Is this a new problem? Is any of this related to macOS Server?

There will probably be more questions but these will do to begin with.

I can add email accounts for Exchange Server using the Internet Accounts preferences pane in System Preferences with no issues. I can also do the same in the Mail App again for Exchange Server. I've also used the Outlook app to add email accounts from different email providers with no problems, furthermore I can do the same thing with the Mail app. Perhaps there's something else going on?