Failed to convert DNS records for subscription via Plesk Migrator: encoding with 'idna' codec failed (UnicodeError: label empty or too long)

Symptoms

• Plesk migrator logs returns the error:

CONFIG_TEXT: ...
=|I|MT|core.reports.printer|||- Client 'john.doe'
=|I|MT|core.reports.printer||| |
=|I|MT|core.reports.printer|||- Subscription 'example.com' 
=|I|MT|core.reports.printer||| | 
=|I|MT|core.reports.printer||| `- error: Failed to convert DNS records for subscription 'example.com' 
=|I|MT|core.reports.printer||| Migration for that subscription is considered completely failed. No further actions are performed for it. 
=|I|MT|core.reports.printer||| Migration tools tried to perform operation in 3 attempts: encoding with 'idna' codec failed (UnicodeError: label empty or too long) 
...

• On Source server, the DNS zone shows a record with . as value:

mail.example.com IN MX 0 .

Cause

Incorrect DNS record on the source Server breaking the domain migration to destination server

Resolution

1. Log into Plesk (to source server)
2. Go to Domains > example.com > Hosting & DNS > DNS menu
3. Correct/remove the incorrect DNS Record
4. Under Plesk Migrator on Destination server, click on "Select subscriptions to migrate", select the affected domain/subscription and then migrate again