Seaquel
SQL Server error code

SQL Server error 2709

SQL Server raises error 2709 at severity 16, which marks a problem with the query or data that you can correct.

Column '%.*ls' in %S_MSG '%.*ls' cannot be used in an index or statistics or as a partition key because it does user or system data access.
Msg2709
Severity16
Group2000–2999

Source: Database Engine events and errors