Seaquel
SQL Server error code

SQL Server error 6921

SQL Server raises error 6921 at severity 16, which marks a problem with the query or data that you can correct.

XML Validation: Element or attribute '%s' was defined as fixed, the element value has to be equal to value of 'fixed' attribute specified in definition. %S_MSG %s
Msg6921
Severity16
Group6000–6999

Source: Database Engine events and errors