Can't charge credit cards in TRBO

Looking for help from anyone using TRBO. I'm trying to set up our instance and while everything appears to be working correctly; I can open the app on the tablet, I can look up a patron and cart a ticket I can't get credit cards to work. When I attempt to type in a credit card number I get a message that says 'Invalid credit card' and nothing happens. Has anyone else experienced this? I've uploaded our cert and followed all the install steps but this is the one thing I haven't been able to solve and I need to have the tablets ready for an event on Saturday. I have a help ticket in for this but thought I'd check with the collective group to see if others have had this issue. We're using Samsung Tab A tablets with no card swiper.