I removed the function from the WHERE and replaced it with a local variable:

AND CD_DW_INSERT_DATE > @Date

I got another problem on a JOIN.

Found filtering columns wrapped inside User-Defined Function call.

AND PTD.Ptd_trans_process_date = CypressStaging.dbo.Fncconvertas400date(ExtCov.Last_change_date)

The function dbo.Fncconvertas400date converts AS400 Date format to SQL Server Date.

I do not know if and what I could do for this?

Thanks again.