A domain is migrated without hosting: mailmng-outgoing failed: ERROR:outgoing:column name is not unique

Symptoms

• Migration to Plesk finishes with one of the following warnings:

  PLESK_ERROR: Failed deployment of domain example.com
  Warning:
  Execution of /usr/local/psa/admin/plib/api-cli/domain.php --create example.com -owner user -do-not-apply-skeleton -notify false -guid 056529ff-e402-463a-aa35-f82d124c4480 -creation-date 2015-03-09 -ip 10.10.10.10 -ignore-nonexistent-options failed with return code 1. Stderr is An error occurred during domain creation: mailmng-outgoing failed: ERROR:outgoing:column name is not unique

  OR

  PLESK_ERROR: Failed to deploy subscription 'example.com'
  Migration for that subscription is considered completely failed. No further actions are performed for it.
  Migration tools tried to perform operation in 2 attempts.
  ----------------------------------------------------------------------------
  Attempt #1 failed with the following error:
  Unable to create subscription 'example.com'
  ----------------------------------------------------------------------------
  Attempt #2 failed with the following error:
  Subscription already exists on target server: most probably it was created at the previous attempt,
  but migration tools are not sure if it was created correctly.
  It is recommended to:
  1) Resolve the original issue that caused subscription creation to fail,
  delete subscription, and then run migration again.
  OR
  2) Ensure that created subscription is fine, or the original issue is minor,
  then simply run migration for that subscription again.

  OR

  PLESK_ERROR: Attempt #1 failed with the following error:
  Unable to create subscription 'example.com'.
  Command execution failed on the local server with non-zero exit code.
  command: /opt/psa/bin/subscription --create example.com -hosting true -hst_type phys -login customer -passwd '' -ip 203.0.113.2 -do-not-apply-skeleton -notify false -owner customer -service_plan Default Domain -force -guid 56f1498d-c4c8-439e-9b67-1e73715b5f5a -creation-date 2017-08-24 -ignore-nonexistent-options
  exit code: 1
  stdout:
  stderr: ERR [util_exec] proc_close() failed ['/opt/psa/admin/bin/mailmng-outgoing' '--add-subscription' '--main-domain-name=example.com' '--out-limit=200'] with exit code [1]
  An error occurred during domain creation: mailmng-outgoing failed: ERROR:outgoing:UNIQUE constraint failed: domains.name

• The subscription and its system user have been created, but the domain has No Hosting type. No data has been restored.

Cause

The subscription already exists in the outgoing mail control database on the destination server.

Resolution

1. Connect to the destination Plesk server via SSH.

2. Remove the subscription in question from the outgoing mail control database:

   # /usr/local/psa/admin/sbin/mailmng-outgoing --remove-subscription --main-domain-name=example.com

3. Re-sync the subscription.