ISSUE: Move Mailbox step fails immediately with error: ' Cannot process argument transformation on parameter 'RemoteHostName''

Overview

When mapping a user and the job begins, the Mailbox Move step will fail with the error below:

Execute_HYBRID_MoveMailboxToO365: An error occurred during Exchange Online Powershell | Cannot process argument transformation on parameter 'RemoteHostName'. Cannot convert value "mrsep.mydomain.com " to type "Microsoft.Exchange.Data.Fqdn". Error: "'mrsep.mydomain.com ' isn't a valid SMTP domain." | Result: Not received [ProcessResult]

The error is caused by a trailing space at the end of the domain name. In this case, we can see a space after the last "m".  

However, when reviewing the Remote Host setting in the UI, there does not appear to be a space if you put the cursor at the end of the string. 

Solution

1. Clear out the entire string from the Remote Host field

2. Paste the string into Notepad and confirm there are no trailing spaces

3. Copy the string to the clipboard and paste it into the field

4. Save the template as a new version

5. Unmap the failed migrations and remap them to the new template version

6. Monitor the migrations