Seaquel
SQL Server error code

SQL Server error 8669

SQL Server raises error 8669 at severity 16, which marks a problem with the query or data that you can correct.

The attempt to maintain the indexed view "%.*ls" failed because it contains an expression on aggregate results, or because it contains a ranking or aggregate window function. Consider dropping the clustered index on the view, or changing the view definition.
Msg8669
Severity16
Group8000–8999

Source: Database Engine events and errors