My iPhone 4s and my wife's iPhone 4 both are having the same issue. Every couple weeks the phone will suddenly not be able to make or receive calls. You dial a number and it will act like it's dialing but never connect. The other phone that you are calling will actually ring and be answered but it's like the iPhone we call from just can't connect to talk. Nothing else is wrong with the phone. You can exit the phone app and go do anything else but when you return to the phone app it still says it's trying to make the call. When you press "end call" the button is greyed out but nothing ever happens. It seems strange that this would happen on 2 completely different phone models. 1 phone is from Thailand and factory unlocked. The other is from Canada and also factory unlocked. AIS says it's not their issue and I agree. The Micro sims seem to work fine in another test phone. The only solution so far is to restore the phone which is annoying. Anyone have any experience with this? Perhaps it's an issue with one of our apps? Or maybe a problem with iTunes since we sync on the same computer.

well i had the same problem today and most of my friends too, strange we all had it today

Btw the only fix i have found is reset all settings

i also noticed this problem happened while it was searching for network and after a restart this occurred

goodluck

This has been a recurring issue for the last few months or so. I go through Apple's steps of troubleshooting but the only thing that works is a restore. It's got to be an issue with AIS, iTunes or an app no? Too much of a coincidence that both phones would do the same thing. Getting ready to restore my wife's phone yet again this morning.

Tried Settings->General->Reset->Reset network settings + a reboot?

Can't imagine you need to actually restore the phone for this, absolutely sounds like an AIS network issue.

I have had this problem too, I'm with AIS and when I had a look through all the settings I found that the Personal Hotspot had been turned on. Once this was switched to OFF all back to normal, don't know if this helps at all.

Take care,

Peter

Tried Settings->General->Reset->Reset network settings + a reboot?

Can't imagine you need to actually restore the phone for this, absolutely sounds like an AIS network issue.

No this isn't only an AIS issue i have been using true move h and stilll having same problems

Tried Settings->General->Reset->Reset network settings + a reboot?

Can't imagine you need to actually restore the phone for this, absolutely sounds like an AIS network issue.

Yes, I tried that. I've tried messing with all kinds of settings to try and narrow it down. I'm hopeful the next iOS update will fix it.

I have had this problem too, I'm with AIS and when I had a look through all the settings I found that the Personal Hotspot had been turned on. Once this was switched to OFF all back to normal, don't know if this helps at all.

Take care,

Peter

Thanks for the idea. I'm sure it was off, but I'll be sure to check that next time it happens.

Just happened again with 4S. I watched the signal disappear and come back. Then I couldn't call or SMS anymore.

I turned EDGE on and off and it fixed the problem this time. Hmmm