Apologies, i may have got that wrong as i was just going off what the customer relayed to me. I have asked them to take a picture of the message and send it to me, it says:-
Account Check Error
Exchange Mail Server (EWS): Invalid server response . HTTP/1.1 404 not found
Please make sure your settings are correct
Does this mean anything to you and if so do you know what settings they may need to change please?
Thanks
Nick