The remote server returned an error: (401) Unauthorized.

Question

I am getting below error when I try to migrate a mailbox from Exchange to Exchange Online.

Error: MrsHttpUnauthorizedException: The Mailbox Replication Service was unable to connect to the remote server using the credentials provided. Please check the credentials and try again. The call to 'https://mail.domain.net/EWS/mrsproxy.svc' failed. Error details: The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM,Basic realm="mail.domain.net"'. --> The remote server returned an error: (401) Unauthorized.. --> The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM,Basic realm="mail.domain.net"'. --> The remote server returned an error: (401) Unauthorized. --> The call to 'https://mail.domain.net/EWS/mrsproxy.svc' failed. Error details: The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM,Basic realm="mail.domain.net"'. --> The remote server returned an error: (401) Unauthorized.. --> The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM,Basic realm="mail.domain.net"'. --> The remote server returned an error: (401) Unauthorized.

Answer 1

Hi @Md. Ramin Hossain ,

Thanks for posting in our Q&A forum.

By research, the error messages you received indicates that the Mailbox Replication Service was unable to connect to the remote server using the credentials provided. This could be due to incorrect credentials or an issue with the authentication scheme used by the server.

To resolve this issue, you can try the following steps:

1. Verify that the credentials you are using are correct and have sufficient permissions to perform the migration.
2. Check if the Exchange GUID property is set on the mailbox.
3. Run the Troubleshoot Microsoft 365 Mailbox Migration tool. https://learn.microsoft.com/en-us/exchange/troubleshoot/migration/moving-migration-mailbox-fails

If these steps do not resolve your issue, you may need to restore the Exchange database from backup, import data from a specific mailbox to PST file, and further data transfer to the re-created mailbox.

If there are any updates, please feel free to let us know.

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