Alternate TCP Connection
By default, our network uses UDP port 1337. If this port is blocked at your location, you can try switching to TCP 443 by editing your .ovpn file.

Change proto udp to proto tcp
Change remote {serverAddressHere} 1337 to remote {serverAddressHere} 443
Change  to 
Change  to 

Source:
https://help.hackthebox.eu/troubleshooting/v2-vpn-connection-troubleshooting