I posted earlier that I resolved this issue by replacing the SIM card. The phone was working perfect for several hours. However, I wanted to se if I had any new notifications by scrolling down on the Home Screen. When I did, I saw a notification that my SD card was moving files..I saw a wheel spinning. I also saw the option to Cancel or Continue. Not being familiar with this message, I opted to select Cancel, however nothing happened. I closed the Notification screen hoping that upon return the message would be gone. I opened up the Notification and saw the same message and spinning wheel. This time I selected Continue and upon doing so, the original error message IMS Service Keeps Shtting Down immediately appeared. I said to myself the F word!@ I was very disappointed having thought I resolved the issue. I then called ATT Advanced Technical Support and after a conference call with Samsung, I was told that additional troubleshooting would be needed to determine if it was a phone hardware issue or a software issue and was asked to go to a ATT store and get a new free SIM card, repeating my earlier fix. I was told to open the Notification window to see if the message regarding the SD card moving files mentioned earlier was again appearing. If it was, I am being told to purchase a new SD disk and restart the phone and open the Notification screen to see if the SD card error message was still if it was appearing. If both messages no longer appears then the issue was the SD card. If the messages reappear, I am to call back to ATT, who will notify Samsung to do additional troubleshooting. If you want to read all of my previous ATT guides troubleshooting, I have two previous posts.
@user2fV9k9oJX1 If none of these steps work and you need additional troubleshooting steps you will have to call back in for it or respond back on this post. Did you do any of the troubleshooting steps you just mentioned?