I can't make connection with exchange mailadress

Hello,

On my PC I can use a exchange emailadress.
When I export this emailadress with the Qr-code or when I want use this emailadress to the app on my smartphone I get an error " Can’t make connection, check emailadress or password".
I also use a IMAP emailadress and that works good on the app on my smartphone.

Who can help me !!!

Thanks in advance