Pepwave AP Mini: Guest Wifi won't go to Captive Portal

I currently have Pepwave AP Minis. They have the latest 3.6.0 Build 1805 firmware on them. I have them setup with a guest wifi to go to a captive portal page. When users try to connect to the Guest wifi network it is not taking them to the captive portal page. It brings up a page msftconnecttest.com and says that there is no internet connection. The customer has multiple locations in different counties and this issue is only happening at two of them. The other locations are able to get to the Guest wifi captive portal page without issues. The firmware on all the APs is the same, I have also tried rolling the firmware back to see if that was the issue and still no luck. I also have rebooted and factory reset the APs, and also rebooted the network equipment. If I turn off the captive portal page on the Guest wifi it will connect to the internet with no problems, only when turning captive portal on will it say there is no internet and it won’t direct to the captive portal page. I have even tried creating a new Test Guest wifi with the same settings as the Guest wifi and it still will not direct to the captive portal page. Does anyone have any suggestions on what the issue might be??