Seaquel
SQL Server error code

SQL Server error 7991

SQL Server raises error 7991 at severity 16, which marks a problem with the query or data that you can correct.

Clustered columnstore index '%.*ls' on table '%.*ls' has a missing dictionary on column id %d and rowgroup id %d. Restore the data from a backup.
Msg7991
Severity16
Group7000–7999

Source: Database Engine events and errors