I have had an intermittent problem with IPTV channels for several months with different versions of firmware.

Often when I change to an IPTV channel, the video appears for a split second and then the screen and the digital audio both go dead. I have just found that the analogue audio continues to function after the digital video and audio cease and when I change channel to a satellite or cable channel the digital video and audio signal is restored. I am not sure if the problem has to do with the HDMI connection to my LG TV or with the Enigma box. There is a similar intermittent problem when I replay recordings of IPTV channels. There are 4 HDMI inputs to the TV -a Skybox, a Forrester Z8 IPTV box, a Yamaha receiver and the Enigma box, but only IPTV channels on the Enigma box are affected. Has anybody any suggestions about what might be happening? Any suggestions would be welcome.