Skip to main content

Why can't I connect to the display?

For an optimal experience, please ensure you are using the latest version of Safari, Chrome, or Firefox that supports H.264. Certain browsers, such as Chromium, do not support H.264 and are not supported for using Corellium.

Additionally, certain enterprise network firewall settings can prevent the display from connecting properly, resulting in a black or grey screen.

Troubleshooting the WebRTC Connection

If you see a message saying "we cannot establish a webrtc stream," there is likely an issue with the STUN/TURN connections.

Cannot establish a WebRTC stream

Follow these steps to troubleshoot:

  1. Make sure the error reproduces across multiple browsers including Chrome and Firefox. (If the error is only occurring on certain browsers, try restoring the browser's default settings.)
  2. Open Chrome with all other tabs closed and navigate to the built-in WebRTC analysis tool chrome://webrtc-internals. Navigate to WebRTC Internals
  3. On a new tab, log in to Corellium and open a device that is turned on.
  4. After opening your device, you should see the WebRTC-Internals tab fill up with information.
  5. Inspect the WebRTC-Internals results. If you notice any errors being reported on this page, please expand those events and investigate.
  6. Save the results as a JSON file by clicking Create a WebRTC-Internals dump at the top-left then clicking the Download button. You can share this file with your IT department or with Corellium support for further troubleshooting. Create a WebRTC-Internal dump

In most cases, a firewall setting will block a particular port or range of ports that are required for our display server. Your network administrator may be able to assist in troubleshooting these network settings.

Additional Cloud Troubleshooting

This section is intended for customers using Corellium's Cloud SaaS solution.

Please check if your network firewall or proxy is blocking TURN does not require any ports other than 80 and 443; however, certain types of network proxies can interfere with TURN.

If your firewall and/or proxy is blocking, you might see an Error 701.

STUN binding request timed out.
url:, TURN allocate request timed out.
TURN host lookup received error.

Additional On-Site Troubleshooting

This section is intended for customers using an On-Site Corellim appliance.

Please confirm that the following ports are not blocked between the browser and the Corellium server:

  • 22
  • 443
  • 8086
  • 8088
  • 27820
  • 27821

Check the configuration

Your configuration is stored under /etc/turnserver.conf. Make note of your:

  • realm, such as
  • incoming-port, which defaults to 27820
  • alternate-port, which defaults to 27821

Check the logs

Check the system logs for errors.

journalctl -u turnserver -S "1 hour ago"

You may see a response showing the realm, the local IP/port, and the remote IP/port:

May  3 21:48:24 abcdefg-1 turnserver: 365: session 000000000000000000: closed (2nd stage), user <webrtc:0000000000> realm <> origin <>, local, remote, reason: TCP connection closed by client (callback)