If the issue is occurring for more than one game then it is most likely something blocking WeMod from either downloading correctly (ie, a network firewall) or injecting into the game (ie, an antivirus).
Try out the troubleshooting here: “Wemod failed loading the cheats into your game” / “We’re having trouble downloading the cheats” - WeMod Support
Your educational institution likely has a security feature that is beyond your control, as stated in the link above. There are a couple of recommended VPN options. If those don’t work you could try seeing if you can download WeMod via a different internet connection, such as at a friend’s house or a local fast food restaurant/coffee shop.