I had to change out my Dexcom sensor today and I put the new one on the back of my arm. It’s a bit tricky but I’ve found those spots work better for me in terms of accuracy and maintaining good signal connectivity with the receiver and my phone.  Unfortunately, a short while later, the new sensor failed while in the middle of warmup.  I’ve had to start the process again and also place a call to Dexcom to get a replacement sensor.  To say I’m frustrated by this would be a massive understatement.