NM: Error trying to migrate a user: "Failed to open document: You are not authorized to perform t (4311601)

Issue

Error messages when testing Notes to Exchange Online migration.
Error: Failed to open document: You are not authorized to perform that operation

Solution

Confirm you have Manager access to the source Notes mail files you are migrating from the Domino server.

If you open the mail file you are migrating with the Domino ID you are using on the migration workstation, is the Access level set to "Manager"? This would indicate the Notes ID you are using truly has Manager access.

Consult the requirements documentation for Notes Migrator to confirm your environment meets the minimum requirements

Outlook must be the default email program on the migration workstation, and you must be logged into the PC with local admin privileges.

You must be using a Notes ID with access to read your Domino directory and manager access to the source mailbox data, and be able to access Notes from outside applications (CMT for Exchange).

Finally, you cannot have restrictions on your network or workstation that prevent the automatic creation of MAPI profiles or PST files, nor any applications which take over or block the use of port 80.

The migration account must have "Full Access" permissions to the destination mail store.
Your migration workstations must be log into the same domain as the on-prem Exchange servers.