Hello,
Depending on the network I am connected at the firewall does not let me navigate in several safe web pages, even if they have the same profile. For instance, when I am connected at Alicante University network the firewall shows me and let me navigate in gmail, youtube and so on; but, when I am connected at UMH University network a “You can not access to this web page” shows up, even if I try with several internet browsers as mozzila, chrome or Edge.
When I disable the firewall, when I am connected in the UMH University network, I am able to access to gmail or youtube, therefore it must be something wrong with the firewall. I do not know about port conections, or firewalls rules as I have not studied network systems or whatever you should study for knowing how to configurate this rules. Please, it is very basic to access to gmail or youtube, how do I configurate it in order to access this web pages safely?
→ https://support.avast.com/article/25/ (Firewall FAQ)