If you are unable to access the pairing web page on the guest smartphone, it may be due to a network issue or traffic blockage. Here are some steps to help you troubleshoot the issue:
Verify that the network configuration is correct, including the VLAN, IP, and netmask. Ensure that the server and the guest device are on the same network and can communicate with each other without any limitations. Verify this by pinging the guest device's IP address from the server and vice versa.
Check if there is any client isolation enabled on the router that could be blocking the traffic between the server and the guest device. If so, exempt the server from client isolation, allowing it to reach every single client and vice versa.
Ensure that there are no firewalls or security software that could be blocking the traffic between the server and the guest device.