Mara tz 1509 4K HDMi not giving audio outcome while connecting LGCX 2Number ARC port

[Sarfraz]

I have purchased LGCX recently for which I am trying to connect the given 4K DHCP for better output. But it's not giving the audio output and showing mute error all the time on display. When I connect the same cable to the normal arc given port 2, it works properly. Can anyone pl suggest how to get through to get the best results.