Exchange mail not incoming in Mail

Since I updated my MacBook Pro to macOS High Sierra, my Mail app has been acting strange.

At first it synced all my mails (through an iCloud, a Gmail as well as an Exchange account), but today I've not received any more mails on my Exchange account. I'm receiving the mails on my iPhone, so I know it's not the server or anything. Mails are coming in on the other accounts though.

I've tried disabling the Exchange account, removing and re-adding it as well as testing if it sends/receives. When I tried to send a mail from the account to myself (same e-mail address), the app crashed and started looping as in starting with a new message window, crashing again, opening,...

I really don't know what to do because macOS High Sierra is brand new and I can't find anything on the same issue.

If you know a solution, feel free to post it here.

Thanks in advance!

Greetings

Vince