Yes, it is the module that gives the error:

After more and more fussing, (copying code from the module into a test file) I did manage to get an answer from the server.

User authentication failed.

But... I can login to what I think is the soap server for the exchange

exchange.mydomain.com/EWS/Services.wsdl

with my username

username@domain

and password.

I tried changing the username in the code to

domain/username

and it still complained about unauthorized .

I have been trying all sorts of combinations, and getting nowhere.

I get the feeling I might be able to get this to work IF I can figure out the correct authentication. But I am stymied.