Safari can't open the page because the server cannot be found

I'm trying to connect to the server login page of my college wifi but safari is showing the above error .I connected Lan cable of the same Network to a windows laptop and through hotspot connected to the server login page and it worked but when i'm using college wifi it is not working.Till yesterday it was working just fine but suddenly it started giving the error.

This is when i'm trying to connect from the wifi.

The page is opening when i'm connected to the hotspot created by windows laptop from the same Network.

I have tried different browsers but it doesn't work.