Hi mdpeterman,
I apologize that you are having issues with your connection. I personally have never heard of any issues with connecting to VPN over the network, but it could be because you don't have Enterprise Data on your iPad.
I would recommend that you send a Private Message to ATTCustomerCare is part of the AT&T customer service team, They may be able to resolve your Issue. You can expect a reply via return PM(Blue envelope top right of screen) between the hours of 7am-10pm CST Monday - Friday, should hear back within 2 to 3 business days.
Additionally you can contact tech support over the phone might be able to troubleshoot further. Their direct number is 1-800-801-1101.