Should have used a vpn...
Your best bet is forgetting and trying to reconnect, reconnect on a vpn, or flat out going to higher up at your school and tell them you can't connect for some strange reason
Also if your going to use a vpn use one from https://www.privacytools.io/providers/vpn/, I highly suggest Mullvad because of they have the best security for a vpn out there, cheap, and have a nice wide variety of payments for anyone including mail in payment.
Don't be too cheap and use a free vpn though, that's just being stupid.
Depending on the network, this may not be an option.
Back in Uni they blocked certain VPN protocols which I used to remote access home, although strangely it depended on which network you were on e.g. my room allowed OpenVPN but not PPTP (which was better for SMB transfers) but the classrooms were the reverse.