I recently bought an (AT&T) LG G2 off eBay, as my iPhone 5S just wasn't cutting it for me.
The day before it came I went into AT&T and asked for a new nano-SIM, it was given to me with no questions asked. The next day, I got it, put the SIM card in, and called to activate it. Everything went fine with customer service, and it activated with no problem, or so I thought.
Everything was looking good, and before I got off the phone with AT&T, I rebooted just to be positive. Once it was back on, I realized in the status bar in the top left it said "Roaming Indicator Off". I told the rep, and he said that was very weird, so we began troubleshooting. Around a half an hour into this, I received a text, I went to go respond to it and when I pressed send it said "No USIM Card". I told him about this as well, so we began troubleshooting both issues.
After about an hour he bumped me up to Android technical support, where I painfully continued with troubleshooting. During all of this I accidentally tried to make a call, and voila, it all went away. The status bar now said "AT&T" and I was able to send texts just fine. I told him about it and just said "That's weird, but awesome!". I rebooted the phone one more time just to make sure, and what do you know, it did it again. The same message came up in my status bar, as well as the inability to send texts.
There was a lot of things tried to fix it, including a master reset, the manual configuration of APN's, and a different text message center address. Trust me when I say, we've done just about everything possible. In fact, the next day he called me back with an LG rep on the line, they too couldn't figure it out.
At first they thought it was a hardware problem, but since making one phone call after a reboot fixes everything, they're leaning toward software. However, there was nothing else they could do.
I guess it isn't really that big of a deal, considering I can just make a call everytime I restart my phone. But I'd really like to get rid of the problem completely.
Thanks for any help you may be able to offer!