Seaquel
SQL Server error code

SQL Server error 6813

SQL Server raises error 6813 at severity 16, which marks a problem with the query or data that you can correct.

FOR XML EXPLICIT cannot combine multiple occurrences of ID, IDREF, IDREFS, NMTOKEN, and/or NMTOKENS in column name '%.*ls'.
Msg6813
Severity16
Group6000–6999

Source: Database Engine events and errors