Some calls go straight to voicemail

[johnnybaloney]

Hello, I'm getting pinged about people trying to call me and leaving or not voicemail messages.

My phone is on, network is fine, I can get another person at home to call me no problem. Yet, yesterday all calls from 111 went straight to voicemail, today my GP called and was sent to voicemail twice before succeeding on the third attempt.

It's annoying as these are the kind of calls where you cannot simply call back. You have to keep your fingers crossed that they will call again and get through otherwise you have to arrange things from scratch again, a PITA.

Here's how it looks, notice the time of the message. It was received at the same time as the person was trying to call. The phone was right next to me on my desk but I got nothing apart from this message. At 14:45 when they tried again the phone rung.

I don't know if this is related but sometimes when I try to call the first attempt fails. I then retry and it starts calling.

[bristolian]

Do you have any problems making calls?

If you're using Android, does your phone show a VoLTE indicator next to the coverage indicators?

Are you able to use mobile data whilst on calls?

Are these missed calls limited to one geographical location, or are they more generalised?

[johnnybaloney]

Hi,

Sorry, missed your response. This is still happening. I was just waiting for a call, then suddenly got a message about a new voicemail. The call didn't go through, there is no entry in the call history, as if my phone was off. It doesn't always happen just as described in the original post. For example, a couple of days ago I received a call from a scammer, they went through fine.

This is how my signal indicator looks like at the moment:

I don't think I've tried that before, but I turned off wifi, I'm currently calling, and no there doesn't seem to be data available, websites don't load while I'm on the call. The call finished, I can browse the Internet again and 4G is displayed on the notification bar now.

I don't receive that many calls or travel around so I only observed this behaviour in one geographical location.

[bristolian · Accepted solution]

What you've described is where you're not using 4G-voice, but your phone is falling to 2G for calls (known as CSFB)

Android phones should have an option somewhere in the settings for "4G calling" or "VoLTE", if the menu option isn't there it should be on by default. Yours is off, and correcting that is the first step.

[johnnybaloney]

Are you suggesting that the delay to switch between 4G and 2G is the culprit?

I don't think I have that option available, there is no Enable VoLTE setting on my phone:

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Android 10, Android 11 or Android 12

1. Make sure your specific Xperia device model and network subscription support VoLTE.
2. Find and tap Settings → Network & Internet → Mobile network → Preferred network type → 4G (preferred)/3G/GSM.
3. Tap the switch beside Enable VoLTE to turn the feature on. If Enable VoLTE isn't available, contact your network operator.

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[bristolian]

It could well be the culprit, at the very least it's something to eliminate.

4G-calling gives numerous advantages over 2G. Is your (presumably Xperia) device EE-supplied?

[johnnybaloney]

Thanks, that's interesting. I'll try switching off mobile data when I have no need for it then, see if the issue persists. Shame it's not easy to replicate but I'll try and see if this workaround works.

No, never had an operator supplied device in my life.

[bristolian]

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@johnnybaloney wrote:

I'll try switching off mobile data when I have no need for it then, see if the issue persists.

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That is unlikely to make any difference. It's not the "activation" of mobile data that alters the behaviour, but the "lack" of VoLTE.

It's almost certainly worth doing the opposite and leaving data enabled - it's a very good test of whether you're connected to 4G or not.

Test calling your phone from another phone, is as a good a test as someone else calling you. The phone shouldn't be differentiating, and it saves you waiting for someone to call you.

[johnnybaloney]

Right, I must have misunderstood. I thought the switch 4G -> 2G and the associated delay when the call was being received may have been the cause of it not always going through and ending up getting redirected to voicemail. And that the presence of VoLTE would've eliminated that switch, as right now I can only have either 4G for data or 2G for calls but with VoLTE I would have 4G for both. But since there is no VoLTE support on my device by the look of it I though eliminating the switch by sticking to 2G might help.

This sounds plausible to me especially as I often also have trouble initiating the call from my side. I have to try several times like trying to start up an old car before the dialling eventually happens.

[bristolian]

With mobile data disabled, and VoLTE not being used, 4G offers you no benefit.

You may notice reduced coverage in some rural and/or indoor locations as a result.