I am unable to register the PostgreSQL or MSSQL database server in the Plesk interface.
The PostgreSQL icon is grayed-out and I am not able to start the service in Plesk. Nevertheless, it is indeed running.
The Plesk Panel license does not have PostgreSQL/MSSQL database server support. You may verify this at Home > Tools&Settings > License Management:
It is necessary to add Power Pack to the Plesk license. Please contact our Customer Support for assistance with this.