Seaquel
SQL Server error code

SQL Server error 1466

SQL Server raises error 1466 at severity 16, which marks a problem with the query or data that you can correct.

Database "%.*ls" is read-only on one of the server instances which is incompatible with participating in database mirroring or in an availability group. Set the database to read-write mode, and retry the operation.
Msg1466
Severity16
Group1000–1999

Source: Database Engine events and errors