Interactive Flat Panels
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  • Author
    • #32293
      Chris AndersonChris Anderson


      I am unable to connect to our new ActivPanel Titanium screens. They were installed in November 2020, and are running firmware version I am trying to connect using a Chromebook and the Promethean Screen Share Extension. My board is able to see the device, but when I try to connect I get the message “RTC Failed.” I am able to connect to the board with my iPhone using Screen Mirroring, so it is not a problem with the board itself. Is there a setting on the Chromebook that has to be changed? Thanks in advance!

    • #32304

      Hi Chris,

      Thanks for your post.

      Please ensure your Chromebook is up to date and running the latest version of Chrome.

      We have seen where updating the Chrome books and rebooting them has resolved this issue.

      Furthermore, please update the firmware of the Panel to version 4.3 following the instructions of this article:

      Should this not resolve the issue please feel free to contact us.

      Kind regards,



      Promethean Technical Support


    • #33256
      Jon TuckerJon Tucker

      I am having the same issue.  When using my laptop, it works fine.  On my Chromebook (HP Chromebook 11 G8 EE), I am getting the message RTC failed.  The board (ActivPanel Titanium) is showing firmware update is 4.3.  The Chromebook is up-t0-date.  Do you have any other suggestions?

    • #33270

      Hello Jon,

      Thank you for your post.

      Do you have the same issue if you try connecting via a Wi-Fi hotspot?

      The following Support article provides guidance on the recommended network requirements: It is possible that the webRTC needs to be allowed for mirroring to work.

      Pleas, also clear data and cache from the Screen Share app and test.

      We hope this helps.

      Kind regards,


      Promethean Technical Support

    • #34589
      Richard WhitleyRichard Whitley

      Good morning,

      I’m having the same issues with connectivity. Laptop and Board are up-to-date; both are connected to the same wifi. The connection was working fine about an hour ago. Now, when I attempt to connect using the Screen Share app, I get the message: TransportError.

      Please advise…

    • #34612

      We just had same issue with Transport errors on 3 boards at the same time. Class was interrupted for 30 minutes rebooting and getting boards back so the would work properly. No issues with wifi in the area.

    • #34675
      Bob WaltonBob Walton

      We spent a lot of time on this and found the panel was on a WiFi network that was restricted to Internet access only.  Apparently the panel and user connect to promethean to establish the connection and once established the panel connects directly to the IP address of the user’s device.  If the panel and the user’s device are on networks that can’t see each other, then it gives the RTC failed.  So different VLANs, subnets, etc may be the issue.  We had the device and the panel join the same WiFi network and that did the trick for us.

    • #34710
      Wendy PrometheanWendy

      Hi all,

      Thank you for posting to our community.

      We’re sorry to hear about not being able to connect via Screenshare.

      As you may be aware, additional network ports were added recently to add additional layers of encryption, so you may have to revisit the network requirements if the issue persists and/or clear the cache on the Screenshare app on the ActivPanels and devices themselves.

      Please see this article on the network requirements for Screen Share:

      More information on how the connection is established and why it requires the ActivPanel and Devices to share a network can be found here:


      If the above doesn’t help and you are still having issues, please contact our Tech Support directly so we can look at everything in detail.

      Calling us is the quickest way to get the issue resolved:



      Thank you,



      Promethean Technical Support


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