At the end of February, AT&T began to shut down its legacy 3G network. The shutdown has been nothing short of a complete disaster. It was supposed to mark the end of 3G-only devices working properly on the network. It was also supposed to kill off phones that lacked VoLTE support on AT&T. But instead, not only did it kill off those phones, it also caused many VoLTE compatible whitelisted phones that were supposed to work after the shutdown to stop being able to place or receive calls. Still, if you have a phone that's 3G only or not whitelisted, there is a way you may be able to get it temporarily working again.
How You May Be Able To Get Your Non-Whitelisted Phone Working Again On AT&T
While on Reddit today, I noticed a thread where a user with Red Pocket on AT&T said they have a 4G LTE capable non-whitelisted phone. The user set their phone to use 3G-only networks, and has been able to place and receive calls since the shutdown.
That got me thinking. Could I get my old phone working again?
I still have a Motorola G4 Plus active on Good2Go Mobile using the AT&T network. The phone is not on AT&T's whitelist and cannot use VoLTE for calls on that network. When the shutdown started, I was still able to use the phone for a few weeks to make and receive calls. After that though, it stopped working, that is until today.
Following the example set by the Reddit user, I changed the preferred network access settings of my phone. It had been set at GSM/WCDMA/LTE. With that setting, I got an LTE signal, but calls have not worked in a few weeks. However, by changing the setting to GSM/WCDMA preferred, I got an HSPA+ signal. HSPA+ is a type of 3G network with faster data speeds than standard 3G. With that setup, I became able to place and receive phone calls again.
So if you have a phone that stopped working, you may be able to squeeze a little more life out of it by changing its network settings to something other than LTE. This may also depend on if AT&T has really shut off its 3G network in your area or not. I'm not exactly sure why this fix has worked, but I think I have a pretty good guess.
My best guess as to why this worked in my area and for the Redditor is that AT&T hasn't fully shut off its 3G network in some locations. If you have an LTE phone that isn't VoLTE capable, in order for it to place or receive calls it has to drop down to a 3G network for the call. This is normally done seamlessly with no interaction from the user needed. I believe AT&T's network must have signaled to non-VoLTE LTE phones to drop down to 3G for phone calls. But with the 3G shutdown in effect, that signaling is no longer happening. However, if you have a phone capable of connecting to AT&T's 3G/HSPA+ network, HSPA+ is capable of transmitting both voice and data at the same time and so AT&T's network doesn't have to tell the phone to switch over to another network type for phone calls. And so if AT&T's 3G/HSPA+ network is still up in your area, this fix may work for you too. For those that are curious, HSPA+ still yields usable data speeds for me at around 9Mbps download and 1Mbps upload with a ping of 98ms. HSPA+ can theoretically support data speeds of up to 42Mbps.
Let me know in the comments if a simple network settings switch got phone calls working again for you on your non-whitelisted phone.