Airtel Xstream box sound issue

[shivamgoelson97]

Hello, I was using a LG smart TV. Initially I was using it with Jio STB and I'm able to hear sound through my Sound-bar connected via HDMI Arc. Lately I purchased Airtel Xstream box with satellite TV support. I have connect my Airtel STB to HDMI 2 port. But I'm not able to listen the sound through my sound bar, Although my sound bar is showing connected through HDMI and Dolby audio but with no sound. If I play something on OTT apps present on my TV and then come to Airtel STB then the sound bar is working fine but just for 10-15 mins and then it gets turned off as it is not receiving any audio at all. Then I have tried connecting STB and sound bar through optical cable but I'm not able to hear 5.1 Dolby either. My 5.1 is not giving me surround sound effect. Then I have connected sound bar and Tv through optical but I have to select PCM input in my TV to hear the sound. If I select Bitstream it is not working and acting just as I have connected the sound bar through HDMI. Is there any solution in which I can experience Dolby 5.1 through my sound bar. Both my TV and sound bar supports Dolby 5.1