Always display your SQL statement somewhere before you execute it. It is
often almost impossible to find a simple problem just by looking at the code
that creates the SQL statement. You can put it into a cell so that you can
see it, or put it in the status bar, or even just put it in a MsgBox. But
always do it, and always include that statement in messages when you are
asking questions about databases.

Seeing your connect string is also generated, you need to do the same for
it.

Is the ClientID a number? If it isn't, you need to put quotes around it.
If it is a number, then you need to show us the complete SQL statement and
the connect string.