Use app called Kodi remote or SYBU

Have been trying to get one of the above iOS Kodi remote apps to work with Kodi on my Amazon Fire box with no luck. My understanding is that ZeroConf is needed to automatically detect my connection but is no longer supported by Android. Have tried to connect using my IP address but still won’t connect (maybe router firewall?). If anyone can point me in the right direction to get it to connect, it would be appreciated….thanks