The symptom is frustrating because it is silent: the site loads, you get matched, and then nothing. A black screen, or a connection failed message. Before concluding the platform is down, it helps to know that real-time video travels differently from the rest of the web - and that this makes it far more fragile on filtered networks.
Why video is a special case
A web page arrives over a single standard channel that every network lets through. A video conversation uses WebRTC, which tries to establish a direct path between the two browsers, over variable ports. Many filtered networks block exactly that.
A very useful practical consequence: the site loading proves nothing about your network's ability to carry the call. The two do not travel the same route.
The causes, by real frequency
- School, university or corporate network. This is cause number one by a wide margin. These networks deliberately filter real-time video, for bandwidth as much as internal policy. The thirty-second test that settles it: try from your phone's hotspot. If it works, you have your answer.
- Browser extensions. Aggressive ad blockers, privacy extensions, browser VPNs: several break WebRTC, sometimes precisely because they are designed to prevent the IP leak it can cause. Test in a private window with no extensions.
- VPN or proxy. Some degrade video to the point of uselessness, others block it. Turn it off to check - the answer is immediate.
- Strict router NAT. Rarer than people think, and mostly out of your control. Serious platforms work around it with a relay server.
- Outdated browser. WebRTC moves fast. A browser that has not been updated in a long time fails on sites that worked last year.
What the relay server does, and why it matters
When the direct path fails, video can travel through an intermediate server, called a relay. Not every platform offers one, and those that keep it for desperate cases let you fail first.
There is a reason to prefer a permanent relay, and it has nothing to do with reliability: on a direct connection your public IP address is visible to the person you are talking to, who can pull it from their browser's developer tools. A permanent relay removes that leak - and incidentally solves a good share of router-level blocking. That is the choice made on PLOXX, where video is always relayed.
Diagnosing it in three minutes
- Try on your phone hotspot. That separates the network problem from everything else in one move.
- Open a private browsing window (extensions are disabled there by default).
- Turn the VPN off.
- Try another browser. If Chrome fails and Firefox works, it is an extension or a setting, not your network.
- Update your browser, then restart it fully.
If all five fail across several different networks, only then does "the platform has a problem" become a credible theory.
"I can see them but they cannot see me"
That is good news in disguise: the connection is established, otherwise you would see nothing at all. So the problem is your camera, not the network - permission refused, or the camera held by another application. It is all covered in my camera does not work on video chat.
A word about school networks
Since it is the most frequent cause, let us be clear: those filters are placed deliberately by the institution, and this article does not explain how to get around them. That is not an oversight. If access is blocked on your school network, the answer is to wait until you are home.
For faults specific to PLOXX and sanction durations, see our help page.