I have been accessing a MS Exchange Server using EWS with Evolution client without difficulty for a while, (OS 13.1, OS, 13.2 and LEAP 42.1 (since December 2015).

Now and again I get messages asking for my credentials again. These messages usually stop coming after a while, even if I do not renew my credentials. I just assume that there is a problem in the handshake with the server that gets solved after a while (e.g. server is down until restarted, timeout on the handshake, etc)

Today, however, although the MS Exchange server is up and running (proven by webmail access), I am continually getting access complaints from the server. Can anyone advise me how to troubleshoot this problem? Is anyone aware of (new) incompatibilities with MS Exchange that EWS and Evolution might need to catch up on?