First of all, 1000 apologies for having never answered your post from over a year ago. Things got crazy in my life and I just put this project on the back burner -- until today.
I implemented your Automate solution and it worked great. Thank you thank you. Now, I'd like to understand why.

C3 and D3 are in the same sheet as the script. The user enters a code into C3. The passwords are stored on the same sheet as well.

It must have to do with using the Event macro: "Private sub Worksheet_Change(ByVal Target As Range)".

I did not mention in previous posts that I had created a worksheet module (unintentionally, it is the default I think) which had other code in it. I can't find where/how to attach a copy or I would. There are 3 code sets in the module. I don't think it had anything to do with it as your Automate solution worked.