Errors attempting to debug an object: "CoUnmarshalInterface returned unknown COM error code" and (4222872)

User has setup Debugging via Debug Setup Wizard and there are no errors in the Debug error log. When the tries to debug any object the following errors occur:

"CoUnmarshalInterface returned unknown COM error code" or "Exception from HRESULT: 0x800706BA"

User has verified Debugging requirements stated in SOL53696 and SOL42701.

SQL Server instance listens on a non-standard port (such as port 1433) and is protected by existing Firewall on server and client.

WORKAROUND:
Add port number to Firewall exception list or disable Firewall if possible.

STATUS:
Waiting for fix to be released in a future version of Toad for SQL Server.

Defect ID was logged to determine and document in Release Notes which communication port to open on the Firewall (both client and Server) when connecting to a SQL Server instance that listens on a non-standard port.