Unable to import mail messages if default location of mailboxes was changed

Symptoms

• Attempt to import mail messages fails with the following error:

  PLESK_ERROR: Failed to connect to the source server and copy mail messages
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  Command execution failed on the local server with non-zero exit code. command: /usr/local/psa/admin/plib/modules/site-import/backend/lib/python/parallels/core/extras/mail-migrator/linux/mail-migrator migrate --source-account-description-file=/usr/local/psa/var/modules/site-import/sessions/mail-migration-6/mail_migrator_source_account_2019-03-30-14-12-38-1_1 --source-message-ids-cache-file=/usr/local/psa/var/modules/site-import/sessions/mail-migration-6/mail_message_ids_cache.cc09547ae0eef5c6623e5ee28834420a --target-account-description-file=/usr/local/psa/var/modules/site-import/sessions/mail-migration-6/mail_migrator_target_account_2019-03-30-14-12-38-1_1 --backup-progress-file=/usr/local/psa/var/modules/site-import/sessions/mail-migration-6/mail_migrator_backup_progress_2019-03-30-14-12-38-1_1.json --restore-progress-file=/usr/local/psa/var/modules/site-import/sessions/mail-migration-6/mail_migrator_restore_progress_2019-03-30-14-12-38-1_1.json --source-ca-bundle=/usr/local/psa/admin/plib/modules/site-import/backend/lib/python/parallels/core/extras/cacert/cacert.pem --target-server-type=dovecot --source-host=203.0.113.2 --source-timeout=30 --stop-mark-file=/usr/local/psa/var/modules/site-import/sessions/mail-migration-6/tasks/2019-03-30-14-12-38-1/stop exit code: 1
  stdout:
  stderr: Internal error of mail migrator: [Errno 2] No such file or directory: '/var/qmail/mailnames/example.com/mail/Maildir'

• Location of mail content has been changed according to the following article:

  How to change the default location of mailboxes in Plesk for Linux

Cause

Mail import does not support customized mail path.

This is Plesk bug with ID PMT-4585 which will be fixed in future Plesk updates

Resolution

1. Connect to the server via SSH;
2. Create symlink to the new MailDir:

   # ln -s /custom/location /var/qmail/mailnames/