Accessing Office 365 Mailbox for a Different User Does Not Work

We are using an admin-account to access other mailboxes. The admin-account does not have an own email-account, it is only used to access other users mailboxes. The necessary rights have been applied, and accessing other users mailboxes with Microsoft.Exchange.Webservices works correct.
Accessing other mailboxes with an old version of Aspose.Email (Version 21.3) works correct.
When using the current version 21.9 of Aspose.Email this does not work anymore.
I guess the reason is, that the admin-user does not have an own mail-account.

The following code is used:
string emailAccountUser = ConfigurationManager.AppSettings[“ExchangeUserName”];
string emailAccountPassword = Cryptography.Decrypt(ConfigurationManager.AppSettings[“ExchangeUserPassword”]);
OAuthNetworkCredential cred = new OAuthNetworkCredential(emailAccountUser, oAuthAccessToken.AccessToken);

                                        WebProxy proxy = WebProxy.GetDefaultProxy();
                                        proxy.UseDefaultCredentials = true;

                                        ewsClient = EWSClient.GetEWSClient(exchangeService.Url.AbsoluteUri, cred, proxy);

calling GetEWSClient throws an Exception with version 21.9 saying that the user does not have a mailbox.

With Aspose.Email version 21.3 the user was not required to have a mailbox to access other mailboxes.

Thank you for contacting support. I logged the issue with ID EMAILNET-40431 in our tracking system. Our development team will investigate this case. We will inform you of any progress.

The issues you have found earlier (filed as EMAILNET-40431) have been fixed in [this update](