Seaquel
SQL Server error code

SQL Server error 6258

SQL Server raises error 6258 at severity 16, which marks a problem with the query or data that you can correct.

Function signature of "FillRow" method (as designated by SqlFunctionAttribute.FillRowMethodName) does not match SQL declaration for table valued CLR function'%.*ls' due to column %d.
Msg6258
Severity16
Group6000–6999

Source: Database Engine events and errors