Make sure your router has UPnP (“Universal Plug-n-Play”) enabled if it has this option. This is needed for the device to be detected on the network.
If using a WiFi client, try instead using a hard-wired client. If the wired client works and the WiFi does not, check the router’s configuration for anything with the word broadcast in it, or anything like wireless partition/isolation/segmentation, and try toggling those options.
If your network is configured to use static IP addresses, check to make sure that the settings (especially the subnet mask) exactly matches that which is defined in the router. Any mismatch, no matter how small, can prevent discovery of the device from working.
If you have more than one router (outside of a mesh system) this creates a network-within-a-network, and you will need to put one of the routers in “Bridge mode”, or have your clients on the same router as the HDHomeRun.
If your router has Access Control enabled, log into it and add the HDHomeRun to the allowed list.