Party chat, can't be heard

question please...when in party chat, I can hear others, but they can't hear me. So far I've tried 2 different xbox ones, three controllers (one new) and three headsets (one new). My friend has tried two controllers and two headsets (one new).
NAT is open on both xboxes, microphone switched on in settings, mic not muted on the headset, volume turned up in settings. I've done a self / solo party test, which worked OK, circle around gamertag responds to voice. Help is appreciated as I'm stuck!

I am having similar issues with a new headset. We can pair and hear the game audio through the headset, but it is not signalling into, nor receiving any chat audio....

Gotcha. I heard a rumor that they are working to fix party chat. Once I was in a party chat and I could hear my party AND hear the in-game chat for Battlefield 4. The rumor was they were going to revert it to the old party chat system by next month. I
forgot where I heard that so I can't source. Again, it was a rumor, so not sure its credibility.

There is a setting that allows game chat and party chat to be heard in stream. I've seen it before, can't remember where it is but it's there. Should be in the twitch app or broadcast settings.

I concur with NAT solution as it has been one of my issues until i figured it out by hitting "check again" till it shows the open message... Some folks you just cant run with or something in their setup screws up your mojo too so...its a mess all the time
with $#1!

Check your network settings NAT status it should be 'open'

I had a similar problem & the headset had a small switch at the rear that had to be switched on. That's all I can suggest next to returning the set for refund?