I think Dia is a serial number where the SQL code needs a text
formating (don't remember but may be something like #MM-DD-YYYY# needed
or similar)

so you will need a Format(Dia,"mm-dd-yyyy") to convert the date in
the regular syntax for SQL.

Tou should try to ask for a fixed date in a string, see if it works

then try to make a dynamic string by "...." & Format(...)
(use a msgbox to see if ok)

then add this dynamic string in the SQL request


this is the "pro-procedure" to be sure and keep time