Seaquel
SQL Server error code

SQL Server error 3104

SQL Server raises error 3104 at severity 16, which marks a problem with the query or data that you can correct.

RESTORE cannot operate on database '%ls' because it is configured for database mirroring or has joined an availability group. If you intend to restore the database, use ALTER DATABASE to remove mirroring or to remove the database from its availability group.
Msg3104
Severity16
Group3000–3999

Source: Database Engine events and errors