I have Googled this exact problem and the limited information regarding how to alleviate this issue was utterly unhelpful, as it does not apply to me. There are no country codes preceding my contact numbers and there never have been. - I send a lot of text messages daily. As of roughly 2130 yesterday, or 18 April 0230 UTC, I can no longer send messages. I can receive them without trouble, both SMS and MMS. I cannot send them. I see only this (big screenshot image): Spoiler Do note the full 5 bars of 4G LTE service coverage. I'm a computer programmer, so the number 65535 seems to indicate some kind of overflow error or upper bound / index bound exception as it is the maximum value of an int primitive in C-based languages (2^32 -1). But the internet says differently - in fact it says nothing helpful. For months, the phone has been extraordinarily slow sending messages and also displaying received messages. It takes between 30 and 60 seconds to display a message on the screen, about the same time to send it from the time I touch "Send," and up to a minute for the app to even open and load. I use HTC Swipe for input, and the lag has become practically impossible to deal with. I know, I know, I should go to the Verizon store. I would prefer not to have to demonstrate the problem, as it would potentially involve showing the Verizon associate the content of my text messages, which is unfortunately out of the question at the moment. It's either business or personal, all quite legal, just so we're clear... Again, as of today, I am unable to send text messages at all. I have attempted to message several people: iPhone 5 on Verizon iPhone 5 on AT+T Pantech something-or-other (non-Android) on AT+T, whom I text very frequently Nokia Lumia (Windows phone, I think) on O2 UK This is completely unacceptable. My data usage is well within the limits of my plan, and every single other function of the phone requiring mobile data is working perfectly fine. If I cannot send SMS, the repercussions could be extraordinarily inconvenient and I simply do not have time to fuss around. I paid generously for this phone, luckily as an upgrade, as I rely on it. I'm sure many of you understand that and subsequently understand my frustration. The phone is completely up-to-date and I tried rebooting it several times. The problem persists. What are my options, exactly? I seem to have hit a wall with regards to my available troubleshooting options, and I have a few rather pressing other projects in the meantime (luckily not mission-critical...yet...) so I'd rather hear from people who actually know their stuff than mess around with my phone on my own! As I said, I'm no Android expert. =/ By the way my phone is NOT rooted. Thanks much for your patience! I appreciate any advice you can offer! EDIT: Additional information: forgot to mention two pretty important things. One, the Messages app usually displays the SMS Error twice and crashes/closes after the second one. Two, I am not the name on the plan. The plan owner/controller (my mother) is currently in Anaheim, California, and I am in Pennsylvania. My father may also be an account holder, but I cannot reach him until later this evening.