Verify that the nsf file is present in the path specified. The TSV file row for that particular user can be edited to enter the correct path to the mail file, and then attempt the migration again.

In most cases, the mailserver name is incorrect, and changing this value to reflect the correct mailserver that contains the NSF file should resolve the issue. If it useless, there is a good program: Lotus Notes Fix Toolbox https://www.fixtoolbox.com/lotusnotesfix.html