Im still having this issue. Not once have iv been able to access voice chat...

Yep. Its frustrating not beeing able to communicate in an MMO. Would love a solution.

3 possible issues could cause it from my understanding

1. Server Lag
2. You're network sucks
3. NAT type

Try resetting the game and putting your console through a power cycle as @toofloated suggested. However, server lag is almost unavoidable however it might not be the only issue.

On the Xbox dashboard:

1. Press start
2. select settings
3. Network settings
4. Test Multiplayer connection

Once the screen says "All good" or gives an error report DO NOT exit out, instead hold LB, RB, LT, & RT all at once to bring up the advanced report.

First, look at UL & DL speeds. Is it at least 1mbps? Second look at latency, ideally latency should be as low as possible and I find that <300ms latency is about the cutoff for detrimental effects on gameplay, anything above that and your gonna have a rough time. If latency is an issue, shut off other network devices that arent in use to preserve bandwith. Third and finally, what is your Nat type? Differing NAT types and poor connections can be severely impacting VoIP capabilities. Ideally, you'll want an Open or at least a Moderate NAT type. If you have a Strict NAT type it can be causing poor quality connection to the game server.

If you're NAT type is strict, you're going to need to get that fixed which is gonna take some playing around with a router.
What you can do is:

1. Log into router
2. Find XB1's MAC address or IPv4 and give it a STATIC address (i.e. 192.168.1.250 is mine on my network)
3. Now either port forward the console, or put it in DMZ hosting if possible (DMZ is easier in my opinion, but do one or the other, not both)

This site will walk you through Port Forwarding: portforward.com/
And heres Microsoft's guide to NAT types:support.xbox.com/en-US/xbox-one/networking/nat-error-solution

Best of luck guys, I hope this at least helps someone

**EDIT** forgot to add something, apologies

Are you getting on during peak hours of gameplay? High server load is a HUGE issue that they really need to fix, especially if your doing PVP. When I have the issue with server lag, usually hopping to a different area or Cyrodiil fixes my game chat.

In any case, submit a support ticket and try getting on during non-peak hours to see if that alleviates it. If not, then try reinstalling the game like you said (Good luck with that Day 1 Patch though...sheesh)

If you send a support ticket MAKE SURE you say

1. How long chat has been unavailable
2. what the error or message says (IE may be due to server maintenence, etc)
3. Resetting does not fix the issue

Hopefully you don't run into the same person I did though when mine was buggy. He basically told me to reset my headset and Get [snip] and closed the case before I had a chance to respond

dashboard, press start over game panel, quit, reload game.

The voice chat menu goes on some sort of disconnect/reconnect or join/exit loop. Try changing channels. Check the bottom left of you screen.

I get a prompt with a 5 second timer telling me it's joining or exiting a channel but I never join or leave one. It's like the voice chat software bugs out, freezes.

Still looking for a possible solution. Voice chat has not worked once and I have tried all possible solutions offered to me. Just says "voice chat is unavailable".

why dont you guys just admit you guys dont know how to fix this...

I have am issue like this, everytime I log in my voice chat is dead, but I can solve just making hard reset to the console then everything start to work fine, now is like part of my day first hard reset then start to play

OR ZOS CAN JUST ADD TEXT CHAT AND OUR PROBLEMS ARE SOLVED