Oracle Message ORA-12324 - cannot use the ROM: link type on a private database link

ERRORcannot use the ROM: link type on a private database link
CAUSEYou can only specify the ROM: link type on a public, not a private, database link.
ACTIONDetermine if there is an existing public database link to the secondary database. If not, and if you wish to establish public access to the secondary database, create a public database link to the secondary database using the CREATE DATABASE LINK command.