School iPad = Restrictions

Your iPad is likely centrally managed by your School. As such, you’ll need to seek assistance directly from the System Administrator who manages your iPad.

If a restrictive policy has been applied, you'll not be able to circumvent applied controls without assistance from your Administrator.

The message "Safari won't open the page as network connection was lost" sounds like a network connection error I.e. no Wi-Fi service or the Wi-Fi router you’re connected to isn’t connected to the Internet. Confirm Wi-Fi is working by going to a website you’ve connected to before from that iPad. If you can connect to that site then it’s likely the sites you’re trying to get to are being blocked by a proxy server. While there are ways to bypass proxy servers this isn’t the appropriate place to discuss how.