iPhone 4 keeps saying "No Service"

hmmm the symptoms sounds very similar to those I had when my sim card died, I wonder if might be the contacts between the sim card and the phone? To understand more of what is going on it might be worth looking at the "Phone" settings (about 4 below "General" on the setttings screen) and see if you lose the information about your SIM card at the same time as the "no Service" message appears. On my phone when things are working right there is a load of info on there including eg Call forwarding and SIM PIN but when the no service message appeared (or if I remove the SIM card) then all that is left is the phone number - and sometimes not even t hatft

I've had this problem intermitently for a while on 4S on Orange and seems to have started pretty much since the EE named network was introduced (though I'm not on 4G).

Anyway... today I was struggling again with the above No Service issue to today after 10+ restarts I noticed my number was not showing in Settings after reset network settings - I followed an older unrelated post https://discussions.apple.com/thread/3401647?start=0&tstart=0 to restored it... it worked but I also got my signal back after this restart.

It could be a big coincidence and unrelated - but worth a try?!

I missed one of the most important meetings in my life that would determine my financial
status for the rest of my life because I couldn't contact them.

I am having the same problem; all of a sudden my 3 month new iPhone 4 dropped cell and 3G service.

I called my cell provider (Rogers, ON) and we tried all kinds of resets. Then I took the phone in and they tried a new SIM card. Then they sent the phone back and I got a NEW one and within 6 hours of reloading it with my info it dropped all service again. My bill is paid and the loaner (a Nokia) they gave me worked fine.

I do not have a land line and use my phone for work related stuff so I am really frustrated. It is at the Roger's store now and they are restoring to factory settings.

For my part, I have uninstalled iTunes and hope that a new installation will solve the problem but some how I doubt it.

WHAT IS THE PROBLEM??

After much faffing the problem on my phone turned out to be the SIM card - as diagnosed by swapping SIM cards with another iPhone. Another symptom that it was a SIM card problem was that the phone settings lost information (usually thre is full screen of call settings etc. it shrank down to just My Number and SIM PIN, and quite often the phone lost its number).

I see a lot of interventions muddling the waters. After extensively experimentation changing SIMs, changing providers, changing phones and changing locations I can very confidently state that the No Service issue IS NOT a SIM, a Carrier, or a location issue. It is an Iphone hardware or software problem. Any statement to the contrary is simply an attempt at trying to absolve the manufacturer. My Iphone 4 developed this and other problems, for example flash light continously on (and now NEVER on) and is now reduced to just an expensive Ipod.

Jose

Sounds like you have had a real bad deal but I do disagree, "No Service" is a symptom which can be caused by many different problems including poor signal, software problems, SIM card problems (as i found out the hard way) and hardware problems. Good luck with getting your phone fixed.

Yes, Jeremy, no doubt a damaged SIM can result in no service. But this discussion is not about that, but rather about the frequent and recurring problems with no service irrespectively of changing SIMs, carriers, or locatios. My SIMs work perfectly with the HTC and the Nokia. On the other hand I´ve tried three different SIMs from different carries of different countries Europe/Africa/North America (including AT&T) and none works.