Thank you for your review. Some public networks (e.g. in schools, hotels, airports, workplaces, etc.) tend to apply restrictions in order to prevent harmful activities and keep track of the traffic flowing. That said, the browser extension uses HTTPS. This is the only connection protocol supported by modern browsers. With that in mind, if you cannot connect using the extension, we suggest using the native Proton VPN app with the Stealth protocol, which was designed for this specific purpose.