iOS Cordova app + staging server

I would like to be able to test new versions of an app through Testflight, but I can’t use its production server due to Hot Code Reload. So I am deploying the code to another server and creating the build of my app with the appropriate --server flag. However, the build can’t connect to this server for some reason.
Anyone ever encountered this (probably common) scenario?

Do you see any error message? Did you try to inspect the device through Safari (see

I got it working. For some reason the problem came from deploying the code to my server (through modulus deploy) after running meteor build and before opening the build in xcode.

I just deploy before building and it goes fine now.