EWS OAuth Authentication

Question

I am able to get a token fine but when I go to Login I'm getting this error:
Rebex.Net.EwsException: 'Internal server error. ExchangeImpersonation SOAP header must be present for this type of OAuth token.

Doing some googling it seems I need to add the "X-AnchorMailbox" header.
But when I try to use ews.ProvisionHeaders I'm not sure what format I'm supposed to put the string in to achieve adding this header to the login request.
I've tried var headers = new List() { "X-AnchorMailbox, yyy@example.com" };
But the login fails with Rebex.Net.EwsException: 'Authentication required.' when I do that.
Any idea how to get this to work? What am I doing wrong?

Here is my sample code:

app = ConfidentialClientApplicationBuilder.Create(clientId)
            .WithClientSecret(secret)
            .WithAuthority(new Uri("https://login.microsoftonline.com/<tenentidgoeshere>"))
            .Build();
        var result = app.AcquireTokenForClient(scopes)
            .ExecuteAsync().Result;



        var ews = new Rebex.Net.Ews();
        ews.Connect("outlook.office365.com");
        var headers = new List<string>() { "X-AnchorMailbox, yyy@example.com" };
        ews.ProvisionHeaders(headers.ToArray());
        ews.Login(result.AccessToken, EwsAuthentication.OAuth20);

Answer 1

Hello,

instead of filling your email address into an HTTP header, please try setting it into an SOAP impersonation header as the first error message said. To do that please use these lines of code before calling ews.Login(...) method.

ews.Settings.Impersonation = new EwsImpersonation();
ews.Settings.Impersonation.SmtpAddress = "yyy@example.com";

Just a note, your second error is most likely thrown from ews.ProvisionHeaders(...) method, not the ews.Login(...) method.

Comments

Thank you! that did the trick!