Hello everyone! I had the same problem but I had to figure it out all on my own and mess with settings to get mine to work.
1. Make sure you do all updates on your phone before you try this
2. Go to settings
3. Go to connections
4. Go to mobile networks
5. Go down to Network mode and make it's on LTE/CDMA and not Global, because if its on Global your HD video calling will not work. Hope this helps you all out.
Have a Great Day!!!