Carrier iPhone 12 Pro Max stops making calls over cellular

[Morac]

I‘ve had my iPhone 12 Pro Max with AT&T for nearly 2 years and never had problems with calling until shortly after upgrading iOS iOS 15.6.

I first noticed a problem where I couldn’t get voicemail, which I fixed using an automated AT&T tool. Lately though the problem I’m seeing if the phone will switch to Wi-Fi calling despite having 3 or 4 5G signal bars. Once that happens the phone will not switch back to cellular and calls stop working if I leave Wi-Fi.

Today I noticed the phone on Wi-Fi calling and it was working so first I tried putting the phone in airplane mode for about 10 seconds and taking it back out. The phone connected to AT&T, but stayed on Wi-Fi calling. I then placed a call and mid-call turned off Wi-Fi. The call dropped and I couldn’t make or receive calls at that point. I then toggle airplane mode on and off again and after that calling worked again and it stayed off Wi-Fi calling.

My house is around 500 yards from a cell tower so the signal should be good, but for some reason the phone just can’t make calls despite being connected to the tower.

I ran a speed test on 5G and got 424 mbps down and 46.3 up, so I shouldn't have issues with calls.

I’ve already tried resetting network settings.

Any ideas?

 

[VineRider]

If you have an ESIM, you might try downloading a new ESIM to the phone. You can do this from your AT&T online account.

 

[arw]

If you don't actually need WiFi calling, you could just disable it completely. (Until the real issue is fixed)
Maybe then you stay reachable via cellular all the time.

 

[Morac]

If you have an ESIM, you might try downloading a new ESIM to the phone. You can do this from your AT&T online account.

I have a physical SIM.

If you don't actually need WiFi calling, you could just disable it completely. (Until the real issue is fixed)
Maybe then you stay reachable via cellular all the time.

The phone seems to be doing what it’s supposed to by switching to Wi-Fi calling when cellular is unavailable. If I disabled Wi-Fi calling I have a feeling I wouldn’t be able to make or receive calls at all when the problem happens.

 

[arw]

The phone seems to be doing what it’s supposed to by switching to Wi-Fi calling when cellular is unavailable. If I disabled Wi-Fi calling I have a feeling I wouldn’t be able to make or receive calls at all when the problem happens.

No matter how good the cellular reception is, WiFi calling is always preferred/established when connected to an eligible network.
You said cellular signal should be quite good. If that‘s the case, then by completely disabling WiFi calling, the problem (switching between cellular and WiFi) shouldn‘t even occur in the first place.

This is of course no real fix.

 

[Morac]

No matter how good the cellular reception is, WiFi calling is always preferred.

That’s not correct. In my experience having had Wi-Fi calling enabled for over 5 years, the only time it’s used is if there is 1 bar or less. It’s never used with 4 bars. If it is, that means there’s an issue with the cell signal.

Of note calls are done over LTE or 5G “data” such that phone calls can switch back and forth between cellular and Wi-Fi. At least that’s how it used to work.

I noticed there was a modem firmware update for the 12 Pro Max in iOS 15.6. Considering I first noticed this problem within a week of upgrading, I’m wondering if it’s related.

 

[arw]

That’s not correct. In my experience having had Wi-Fi calling enabled for over 5 years, the only time it’s used is if there is 1 bar or less. It’s never used with 4 bars. If it is, that means there’s an issue with the cell signal.

Well, seems like it depends on the carrier:

Depending on the carrier, your phone may even keep Wi-Fi calling feature active when you are in an area with good cellular service but connected to a Wi-Fi network. It helps carriers reduce network congestion while providing better voice service to you.