Error enabling postgres feature in sub-server

Hello, I enabled the PostGres db in webmin and then attempted to enable the PostGRES feature in a sub-server. However I received an error as follows.

Creating PostgreSQL database rs …
… PostgreSQL database failed! : SQL create database “rs” with owner=“xxxxxx” failed : role “xxxxxx” does not exist at …/ line 1385, line 1.

I deleted the sub-server and tried creating a new one and still get the same error.

Any help is much appreciated.

Thank you