Seaquel
SQL Server error code

SQL Server error 8673

SQL Server raises error 8673 at severity 16, which marks a problem with the query or data that you can correct.

A MERGE statement is not valid if it triggers both the 'ON DELETE SET NULL' and 'ON UPDATE CASCADE' actions for a referential integrity constraint. Modify the actions performed by the MERGE statement to ensure that it does not trigger both these actions for a referential integrity constraint.
Msg8673
Severity16
Group8000–8999

Source: Database Engine events and errors