Exchange Web Service API and 401 unauthorized exception

Question

When I try sending email using the EWS API, I get the following error: (in message.Send();)

The request failed. The remote server returne

Answer 1

This issue can cause the two way authentication provide by Microsoft office 365. Better create a app password and pass that instead of outlook password.

exchangeService.Credentials = new WebCredentials("email", "app-pwd");