iOS VPN will NOT connect on certain WiFi
Solution 1:
Most schools have firewalls on their network that prevent VPNs from being used. This is because firewall website filtering can be usually bypassed by using a VPN.
So as you guessed, it is something on the network that’s blocking the VPN.
And just so you know I have not found a way to bypass a VPN blocker or firewall(I am also a student at a school with a similar firewall)