This just happened to my note 8 and within a week it happened to my wife's. So the fix is actually pretty easy. But is annoying that you have to go to the TMobile store and get your sim card replaced. After it's replaced, power off your device and press the volume up, bixby button and power button at the same time. Once the blue screen appears (with Android) during bootup you can release all 3 buttons and wait. Once you get to your bios screen. Scroll down to clear cache with volume down button. Select it with the power button. (Warning be sure your selecting clear cache! Not resetting your device! They are right next to each other) After your given the option to reboot. Select that option and the evil message IMS Service has stopped should not come back! Hope this actually helps everyone save some time! (This is my experience from over 45 minutes on the phone with tier 2 tech support, 2 phone calls and a visit to the TMobile store. Also the tier 2 rep said they'd credit my account for the sim card. The employee at the store didn't charge me for it. Just FYI