When testing the ODME connection settings with a target of O365 the following error is returned.
“Failed to validate using auto-discovery. : Autodiscover for 'firstname.lastname@example.org' failed; the mailbox may not exist or may not be licensed: Invalid user 'email@example.com' specified.”
This failure returned by the test connection within ODME does not impact a migration.
Save the connection settings and migrate a user as a test and confirm your data is migrated to the target location as expected.