Bear with me, I'm a low-level user.
We updated Joomla/Virtuemart a few months ago, and ever since then our customers cannot confirm their order (nothing happens) if they have changed the default address from their account to a different shipping address in the shopping cart. If the shipping address stays the same as the address on their account, everything works fine. Change one digit and it does nothing.
Normally, the customer checks the terms and conditions box, clicks confirm order, and it takes them directly to PayPal for payment.
Any help would be appreciated. I'm sure it's just a setting, but we are very basic users.
If you updated "a few months ago" then your versions are most likely out of date. Current Joomla is 3.9.0 and VM is 3.4.3 so probably best to update first and see if that fixes it.
If not the you should provide the live site URL so someone can take a look.
The live site is:
https://ardentoutdoors.com
your using some 3rd party checkout
onepage_generic
I would start there... test with the standard checkout ---