App does not work on iPhone through C-Spire phone company

Hello, I have had this problem for a while and it has persisted through all the updates. I work for a security company and need the app to check on the security systems we put in. My boss who has a iPhone through AT&T works no problem, but when I try to use it on my iPhone through C Spire it just continuously has the dots spinning around in the center of the screen as if its still loading. The app works when my phone is hooked up to wifi, but not when using just cellular data. Please fix this. It is urgent

Swarmer333 about DW VMAX