If you are unable to find the "Cast" icon on the guest device after a successful pairing, it may be due to a traffic blockage between the TriaxCast server and the guest device. This is most likely caused by mDNS or SSDP being blocked. Both protocols must be able to travel in both senses between the TriaxCast server and the guest device in order for the "Cast" icon to be visible. Here are some steps to help you troubleshoot the issue:

  • Troubleshooting mDNS:

To check if mDNS is being blocked, you can use Wireshark on a PC connected to the guest network. Start sniffing the WiFi and enter "mdns" in the filter. If no data is shown, it means that mDNS is being blocked from the guest network and in. To check the opposite direction, connect the PC in the same network as the Cast Server, and apply the same method. 

You can force sending some mDNS data from your phone by opening and closing apps that can be used with a Chromecast, such as YouTube or Netflix. Android devices typically use words as mDNS, while Apple devices use words like "airplay," "homekit," or "iphone."

  • Troubleshooting SSDP:

SSDP is another protocol for both discovery and controlling the Chromecast and can be troubleshooted the same way as above. Use "ssdp" instead of "mdns" as the filter in Wireshark and use port 1900 instead of 5353.