Seaquel
SQL Server error code

SQL Server error 4961

SQL Server raises error 4961 at severity 16, which marks a problem with the query or data that you can correct.

ALTER TABLE SWITCH statement failed. Column '%.*ls' in table '%.*ls' is nullable and it is not nullable in '%.*ls'.
Msg4961
Severity16
Group4000–4999

Source: Database Engine events and errors