Seaquel
SQL Server error code

SQL Server error 8903

SQL Server raises error 8903 at severity 16, which marks a problem with the query or data that you can correct.

Extent %S_PGID in database ID %d is allocated in both GAM %S_PGID and SGAM %S_PGID.
Msg8903
Severity16
Group8000–8999

Source: Database Engine events and errors