Why can't I search? This guide is helpful for people who cannot search hubs due to their internet connection. A hub often requires a user to register before searching and downloading on their hub, and therefore you must take that into consideration. Assuming that you're registered or the hub doesnt require registration and you're still requring problems, then follow these guidelines: Use the "Get IP address" button in connection settings.
Check your firewall configuration. You need to make sure it's allowing or forwarding incoming connections on the port specified in the settings. You have to enable both TCP, UDP and TLS traffic. If you can download files but not search in active mode, this means that the ports are still blocked (use this guide to resolve this).
If the above things don't work for you, you'll have to use passive mode (if the hub allows it).