Seaquel
SQL Server error code

SQL Server error 1456

SQL Server raises error 1456 at severity 16, which marks a problem with the query or data that you can correct.

The ALTER DATABASE command could not be sent to the remote server instance '%.*ls'. The database mirroring configuration was not changed. Verify that the server is connected, and try again.
Msg1456
Severity16
Group1000–1999

Source: Database Engine events and errors