When migrating from Exchange 2003 to Office 365 you may receive the following error on the destination:
“Your migration failed while checking source credentials. The request failed. The remote server returned an error: (404) Not Found.”
Diagnosis:
If you’re using a single master source admin credential for the Migration, the most common scenario, then you should test access to each problem mailbox using the admin credential and following URL format: https://mail.example.com/exchange/user@example.com
If you’re specifying each individual users source credentials in MigrationWiz then you should test access to their mailbox via OWA using the following link format and the individual users logon credentials: If using administrative credentials, change the URL to https://mail.example.com/exchange
If you’re able to access the mailboxes with OWA then it’s likely the issue is something preventing logon to the end user account, this issues can be fixes by following the below:
Review the accounts involved and determine if there is anything that would prevent them from logging in. Check the account tab in Active Directory Users and Computers for checkboxes being checked like:
- User must change password at next logon (make sure it’s unchecked)
- Account disabled (should be unchecked)
- Account locked (if this is the case select ‘unlock account’ and click apply)
- Password never expires (this should be checked in the event the account has an expired password that is preventing logon)
This should resolve the “Your migration failed while checking source credentials. The request failed. The remote server returned an error: (404) Not Found.” error on the Exchange 2003 source.