BLACK SCREEN on webviewer / H264 unavailable



Hello, and sorry for my poor english…

if I use Webviewer I see this:

so I verify all the setting, and in Chrome (75.0.3770.100) I found that the H264 video encoding are not available… why???:



Thanks for reporting the issue.

Have you tried the troubleshooting steps here:

If so, please also try to open Alfred WebViewer in Incognito Mode to see if it works.

Please keep me posted.



yes, tried… but still not work (where is “Incognito mode” in the setting :thinking: ??);

samne problem with Firefox

I have also tried to set the PC firewall to open TCP ports 5222, 443, 3478, 19302 but nothing change…

it is possible that it is a problem of the business network ?.. the Admin tell mi that are no restriction, but…


Tap the three-dot menu in Chrome and you’ll find an option to open a new incognito window.


Let me know if that helps!


Nope, in incognito mode nothing change…



I’m sorry to hear that it doesn’t work. Are you able to watch the live feed from your mobile device?


Yes, with mobile no problem… and at my home the Webview work fine…

and despite what the network administrator says I think there is something here where I work that blocks the audio / video stream…


It does sound like a network restriction or firewall issue. If possible, we suggest you try connecting your PC/Mac to a different network under that circumstances.