Seaquel
SQL Server error code

SQL Server error 6229

SQL Server raises error 6229 at severity 16, which marks a problem with the query or data that you can correct.

Type "%.*ls.%.*ls" is marked for native serialization. It is not marked with "LayoutKind.Sequential". Native serialization requires the type to be marked with "LayoutKind.Sequential".
Msg6229
Severity16
Group6000–6999

Source: Database Engine events and errors