"Port 5005 on the network doesn’t seem to be open or there might be an issue with MTU size."

If you're running into this problem, please make sure that the device is on a network with open outbound TCP/UDP traffic on Port 5005.

  • Screen sharing content is generally transmitted with TCP 
  • Camera video is generally transmitted with UDP

If you believe that has already been done, check out the scenarios below to identify why you might be seeing this Error and what you can do to solve it.

The error occurs on on my computer or mobile device

Nothing happens when I try to begin presenting my screen or when I try to start a conference.

  • If you run into this, this likely means that both TCP and UDP* outbound traffic are blocked on port 5005. 
    • *Even if UDP traffic were allowed, TCP blockages will stop you from even starting a conference.

When I start a call or begin presenting my screen, I get the error, "There appears to be an issue with your network" and then 10 seconds later I'm disconnected from the call with the error, "Sorry you’ve been disconnected, please refresh your browser."

  • This means that outbound UDP traffic is blocked on port 5005.  
    • This also means that you're halfway there! Outbound TCP traffic on port 5005 must already be open in this case. 
  • If both types of outbound traffic are allowed through port 5005, then this may be due to an MTU size restriction issue. 
    • Please allow for packets of size 1360 bytes. 

The error occurs on my Highfive device

The device will not fully boot to the main Highfive screen and I see the error, "Port 5005 on the network doesn’t seem to be open or there might be an issue with MTU size. Please resolve the issue and restart the unit. Contact help@highfive.com for assistance."

  • If you're unable to boot the device to the main screen and you see the above error, this indicates that outbound TCP and UDP* traffic are blocked.
    • *Even if UDP traffic were allowed, TCP blockages will stop you from fully booting the device.

When I try to start a call from my Highfive device, it won't work and gives me the error "Lost connection to the TV" on my device and shows the following error on the TV: "Port 5005 on the network doesn’t seem to be open or there might be an issue with MTU size. Please resolve the issue and restart the unit. Contact help@highfive.com for assistance."

  • If you're running into this issue when trying to start a call with your Highfive device, this means that your outbound UDP traffic is blocked on port 5005 or your MTU size restrictions don't allow packets of size 1360 bytes.

Helpful tip: If you or your company have concerns about opening outbound TCP/UDP traffic on port 5005, you can use the MAC address (found on the back of the Highfive device) to open the port for only that particular device.

Casey Helton -

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