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Hello,
I am trying to migrate from an exchange server 2019 on prem server to exchange online. However I keep getting the 401 unauthorized error. I get it at every point. If i do HCW i get it, test migration availability, setup migration endpoint in m365. Also to note I am using Mimecast as my email gateway. Also get same error from BitTitan's MigrationWiz.
Settings that are set:
MRS Proxy Enabled
Basic / Windows authentication Enabled
Credentials are correct for accounts
Enhanced Protection Disabled
Account has Organization Management and Impersonation.
Here is the error i get with the Hybrid Configuration Wizard. Similar error received when doing other migration attemtpts.
"HCW8078 - Migration Endpoint could not be created.
Microsoft.Exchange.Net.CommunicationErrorTransientException
The call to 'net.tcp://ds0pr14mb5616.namprd14.prod.outlook.com:9821/Microsoft.Exchange.MailboxReplicationService DS0PR14MB5616.namprd14.prod.outlook.com (15.20.8026.17 ServerCaps:FFFFFFFF, ProxyCaps:1FFFFFFFFFFFFFFFC7DD2DFDBF5FFFFFCB07EFFF, MailboxCaps:, legacyCaps:FFFFFFFF)' failed. Error details: 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.com/EWS/mrsproxy.svc' failed. Error details: The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Basic realm="mail.domain.com"'. --> 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 'Basic realm="mail.domain.com"'. --> The remote server returned an error: (401) Unauthorized.."
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question. To protect privacy, user profiles for migrated questions are anonymized.
Hello，
Thank you for posting in the Microsoft Community forum.
I understand that your question is related to Exchange Server. Given the technical nature of your inquiry, I recommend redirecting your question to our specialized forum dedicated to this topic:
Exchange Server - Microsoft Q&A
Thank you for your understanding and cooperation.
Best regards
Jacen
Thank you Jacen,
I have psoted the same question to: Exchange Server 2019 mrsProxy 401 UnAuthorized Error (Trying to Migrate to Exchange Online) - Microsoft Q&A