401 Unauthorized: The credentials used to access the configured mailbox is invalid, or the credentials specified do not have access to the configured mailbox, or you may be have overutilized resources.
The most common problem when encountering this error is that the user name and password specified are not able to access the mailbox. You can verify if the user name and password are correct by testing mailbox access using OWA. If your connector is set to use administrative access, make sure to log in to the mailbox using administrator credentials (because this is what MigrationWiz will do).
If you have verified that the credentials are correct, try re-entering the credentials into MigrationWiz, and resubmit the mailbox for migration. It may be possible that the credentials were specified incorrectly.
Incorrect Login Name Format
If you are migrating from or to AWS WorkMail using user credentials, the login name needs to be the complete user email address.In some environments, when using the format domain\username, the username is truncated to 20 characters. If the username is longer than 20 characters, enter only the first 20 characters of the username.
If you are using administrator login for migration, and have verified that the credentials are correct, but are still encountering the 401 Unauthorized issue, you may need to look into the administrator account's permission.
By performing a grant the administrator permission accordingly to solve the issue.
If you have validated that your credentials are working properly, it is possible that you may have overutilized resources.
Attempt to open your OWA URL from an external network, from a system that is not joined to your domain. If OWA is loaded in a timely manner, then check your server resources:
- Check server CPU usage
- Check memory usage
- Check disk I/O usage using performance monitor
- Check for overutilization of the network