Error occurred during purchase product identifier not valid

Hello. I've recently started having issues with Windows 10 Home. I'm getting an error in the MS Store when I try to purchase gems for a game. This error is happening on more than one game, so its not just one game that is causing this issue. I get the following error when I try to do this:

Code:

Error occurred during purchase product identifier not valid

I've tried the following things:

1. Reboot Laptop.
2. Sign out of MS Store & sign back in.
3. Perform a clean boot of windows.
4. Disable my anti-virus & firewall to see if possibly its blocking this app from purchases.

I tried working with a MS tech person on this but they wanted remote access and I'm not entirely comfortable with that personally. I'm well versed enough that if I have instructions on what to do I do them just fine.

I have recently changed my MS account password & my password on my Laptop login. I have been able to buy gems and things in the past from the MS store with no problem.

I'm running Windows 10 Home, CPU Intel i7 2.00 processor, 16 GB RAM on a Lenovo Y40-70 laptop. I currently have McAfee for my firewall & anti-virus & CCleaner. Any help would be great. Thanks.

Anyone have any ideas?