'Autodiscover service couldn't be located' when trying to access Exchange 2010 account with EWS MANAGED API

Question

I am using Auto discover service Url for a specified e-mail address.

ExchangeService Service = new ExchangeService(ExchangeVersion.Exchange2010);
Service.Cr         


        

Answer 1

Faced this issue for specific user. After checking I found that user has enabled two factor authentication and using his primary password for connection. Solved by generating app specific password and connecting with it. Disabling two factor also worked, but it will take some time to reflect. Not sure why exchange gave "The Autodiscover service couldn't be located." instead of "Unauthorised".