OVH Exchange problem

Hi,

I am new to eM Mail on Mac.

I tried to add my exchange account which is hosted at OVH.net,
but without success. eM always asks me infinitely to enter username and password.

When I try to connect to web interface or EWS service URL:
https://ex.mail.ovh.net/ews/exchange.asmx

I can log in without a problem.

Does someone has an idea?

Ps. Gmail is working