Can stream video from all cameras in group view mode but not individually on IOS

Hi there. I have some remote cameras in a different country. I am able to see streaming video when looking at a group of cameras but when I try to look at an individual camera, I get stuck on authenticating and never connect. These are v2 cameras (1 pan and 2 v2) , all of which exhibit the same issue.
This does work on Android though - so I am assuming it;s something to do with the IOS app and how it streams the group videos vs an individual one.
I want to look at the individual ones so I can zoom in, pan the camera and update the firmware.
I know the WiFi where I have them is not great (about 6 MBs) - but with the Android working and IOS not, that shouldn’t be the problem.
Thanks in advance…