This is one of the most common proxy complaints: settings look correct, but pages just spin or time out instead of loading.
The proxy itself is dead
This is the most likely cause with free proxies specifically. Test the same proxy with a checker tool or a simple command-line request outside your main app to rule this out first before troubleshooting anything else.
Wrong protocol specified
Entering a SOCKS5 proxy into a field expecting an HTTP proxy (or vice versa) often connects at a basic network level but fails to actually route traffic correctly, producing exactly this kind of silent failure.
Firewall or antivirus interference
Local security software sometimes blocks unfamiliar outbound connections on a proxy's port, especially if it's an unusual one, which can look identical to a proxy problem from the outside.
A quick isolation step
Try the exact same proxy details in a different app — a browser instead of a script, or vice versa. If it works in one but not the other, the problem is in that app's configuration, not the proxy itself.