EWS / Oauth configuration

EWS / Oauth configuration


I'm having some issues getting going with EWS and OAuth, and perhaps someone has some input on what I might have missed.

Currently on v11.1.0 Build 11133 - clean install for testing purposes.
When saving the config I get a popup for 365 signin, where I've used the same account as specified in the incoming mail configuration. See the picture for the resulting error message.

If I try saving the config again after that I get a popup where I can pick the account I used the first time, but instead of getting the error message I instead get a login form for Servicedesk Plus in the popup, and login in there results in a 404 error.

Any input would be welcome.
Config/error message: