we are using mediasoup 3 in our product. Recently we got couple of reports for missing (“black”) cameras from some demo sessions with corporate clients. Mediasoup is working great for most of the cases, we are also using Twilio TURN servers (we have tested them and they work), but for certain group of clients we get the missing cameras. The clients are reporting black cameras, because in such environments they are using phones for audio (so we don’t know if the audio streams will work, but I assume it will be the same as video). The problem is that we do not have any way to test or debug on the problem networks or ask the clients to run some specific tests or third party tools. Our best guess at this point is some kind of aggressive firewall or maybe somekind of proxy server that is blocking the WebRTC communication (the TCP socket communication is working as expected). Currently we are trying to collect some statistics on the server and client side and we are hoping they will shed some more light on these issues. But in the meantime I will appreciate any feedback from mediasoup community for simillar issues and / or suggestions how we can identify the source of the issue. Or any guidlines for mediasoup configurations, TURN servers or port ranges that are expected to work best in corporate grade networks.