Exchange Web Service - The remote server returned an error: (401) Unauthorized

Question

I am trying to connect to Exchange Web Service by using email and pwd:

var exchangeService = new ExchangeService()
{
//credentials.UserName
Credentials = new WebCredentials(credentials.EmailAddress, credentials.Password),
Timeout = 60000
};

        // Set the URL.
        exchangeService.Url = new Uri("https://computername.domain.contoso.com/EWS/Exchange.asmx");
        Logger.DebugFormat("Service URL: {0}", exchangeService.Url);

        return new EWSConnection()
        {
            Service = exchangeService,
            Router =
                new RecipientsMailboxManagerRouter(
                    new EWSMailFolder(Folder.Bind(exchangeService, WellKnownFolderName.Inbox), useConversationGuidOnly))
        };

And I got the remote server returned an error: (401) Unauthorized.
It used to be working fine but just last Friday, I got this issue. Can anyone help me please?

Answer 1

Hello,

Various exchange services can be tested with online testconnectivity tool from Microsoft. You may test the EWS connectivity as follows and see it works. If not adjust the code or server settings. If you need further support, please paste the test result here:

1. Open https://testconnectivity.microsoft.com.
2. Select Office 365 or Exchange Server as per your setup.
3. Select Service Account Access and perform Test. Use the same parameters you use in code

Thanks,
Manu

Answer 2

Thank for the tool! I have been looking for something like this to test the connection.

Here is the Exchange Web Services URL, https://outlook.office365.com/EWS/Exchange.asmx, that I am trying to access to.
Unfortunately, I got the same issue.

Answer 3

By disabling MFA my issue was resolved, our system engineer moved our email account out of zone group.......Thanks a lot!!!