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SQL Server error code

SQL Server error 502

SQL Server raises error 502 at severity 16, which marks a problem with the query or data that you can correct.

The SQL Debugging Interface (SDI) requires that SQL Server, when started as a service, must not log on as System Account. Reset to log on as user account using Control Panel.
Msg502
Severity16
Group0–999

Source: Database Engine events and errors