Quote Originally Posted by Bink View Post
I had this exact same issue with my Nexus 5 (N5) and T-Mobile. Calls are great over LTE, but to get this to work I had to change the APN protocol from IPv6, which is the default, to IPv4. I don’t know if this is an issue with the N5, VOIPo or T-Mobile, but I can make and receive calls over LTE now so I’m happy.
Where would I change the APN protocol?

Thanks