Help! Solution for complete breakdown of the Phone app

grapheneuser1234

jarell

grapheneuser1234 Try turning LTE Only off. Seemed to fix the issue for many others.

grapheneuser1234

NetRunner88 It doesn't appear to have anything to do with network, as SMS and internet on the same SIM card worked fine.

de0u

grapheneuser1234 It doesn't appear to have anything to do with network, as SMS and internet on the same SIM card worked fine.

Phone calls do use the data layer, but they are still implemented by the carrier network using a lot of software that can go wrong even if the data layer is working. I agree with NetRunner88's suggestion.

SovereignCopper

NetRunner88 Is there some info about what this reset entails exactly? I clicked it by accident (wanted to long-press to see what the button was about), and while it doesn't seem any of my settings were affected by it, I'd like to be sure.

de0u

jarell Try turning LTE Only off. Seemed to fix the issue for many others.

grapheneuser1234 I've selected "LTE only" since day one, which never had been a problem.

Since there is a problem, something has changed. It is likely that solving the problem will require running some experiments. This particular suggested experiment is fast and easy to run, so running it is probably a good step to take.

grapheneuser1234

Thanks NetRunner88 , I tried your advice but didn't fix the issue.

@jarell I've selected "LTE only" since day one, which never had been a problem.

Upon checking out some other threads on the forum, I'd add that the possible cause may not have been the manual change of date on device but instead a system update to Android 15. Are there any ways to "reset" or "reinstall" the phone app only?

DeletedUser87

grapheneuser1234 the phone app is not the problem. It's just a front end and has nothing to do with failed calls, especially incoming ones. You need to check your connectivity settings. Go to Settings -> About phone -> SIM status (whichever slot is active). Make a screenshot of that, blur out the phone number and ICCID and upload it somewhere like Imgur, then share a link here. Unless we know more info, it's incredibly hard to troubleshoot.

de0u

grapheneuser1234 Are there any ways to "reset" or "reinstall" the phone app only?

You could try:

Power device off, remove SIM card, power on.
Long-press Phone icon, choose "App info", then under "Storage and cache", reset cache and storage.
Power device off, insert SIM card, power on.

Can you report which build number of GrapheneOS you are running? Also, which cellular carrier? How old is the SIM card?

Carlos-Anso

grapheneuser1234 I've selected "LTE only" since day one, which never had been a problem.

Your symptoms is exactly what happens if a carrier, or your configuration, does not support calls over LTE. I would strongly suggest testing with a different Preferred network type than 'LTE only'. Some carriers call this '4G Only'.

It may be you carrier has changed the way things are configured on their network. Could also be that for some reason you do now not get the correct, or necessary, carrier configuration on the phone.

grapheneuser1234

Million thanks for all your helpful advice! The issue is now resolved.

Carlos-Anso Your symptoms is exactly what happens if a carrier, or your configuration, does not support calls over LTE. I would strongly suggest testing with a different Preferred network type than 'LTE only'. Some carriers call this '4G Only'.

I changed the setting to "LTE" from "LTE only" and the issue disappeared. Got a relevant question though, I earlier selected "LTE only" as it was claimed to be the most secure network option according to some online articles/opinions, so how does "LTE" compare in terms of security or attack surface?

de0u You could try:
Power device off, remove SIM card, power on.
Long-press Phone icon, choose "App info", then under "Storage and cache", reset cache and storage.
Power device off, insert SIM card, power on.

Tried and did not fix the issue.

Can you report which build number of GrapheneOS you are running? Also, which cellular carrier? How old is the SIM card?

Build number: 2024110700
SIM card is around half year old.

Last but not least, just want to make a point that there had been no particular change of configuration (other than backdating the device for less than a day and upgrading to android 15) on my end so why the issue occured remained a mystery.

Carlos-Anso

grapheneuser1234 so how does "LTE" compare in terms of security or attack surface?

'LTE only' means you are only open to cellular attacks that target LTE/4G. Other options leave you also open to attacks that target 2G 3G and 5G. You can however disable 2G with the toggle at the bottom of the cellular settings page.

de0u

grapheneuser1234 Last but not least, just want to make a point that there had been no particular change of configuration (other than backdating the device for less than a day and upgrading to android 15) on my end so why the issue occured remained a mystery.

It may remain a mystery!

Carriers change their networks all the time, so even if absolutely nothing on/about your device changes, you may observe different behavior over time.