Unable to send message from domain where mail hosted on Google: 550 Requested action not taken: mailbox unavailable or not local

Symptoms

• The following bounce message is received while sending a mail message to john.doe@example.com on Plesk server:
  

  CONFIG_TEXT: Delivery to the following recipient failed permanently:
  john.doe@example.com
  Technical details of permanent failure:
  Google tried to deliver your message, but it was rejected by the server for the recipient domain example.com by mail.example.com [203.0.113.2].

  OR

  CONFIG_TEXT: An error occurred while sending mail.
  550 Requested action not taken: mailbox unavailable or not local
  Please check the message recipient john.doe@example.com and try again.

• Mail for this Plesk domain is hosted on Google Services.

Cause

Mail domain is present in MailEnable configuration.

Resolution

1. Connect to the server via RDP.
2. Open MailEnable at Start > MailEnable
3. Navigate to Messaging Manager > Post Offices > example.com > Domains: 
   

   

4. Double click on example.com to open Properties window:
   

   

5. Enable Act as Smart Host option and add IP address in the bottom of the list:
   

   

6. Download the following tool from MailEnable: MERoute
7. Unpack the archive and execute MERoute.exe:
   

   

8. In the new window select example.com and click on the OK button to save the change: