Beginning just this past week, I have started having similar issues with Garmin Speed Sensor 2 connecting to Zwift Companion App.
I have been using the Garmin Speed Sensor 2 and Cadence Sensor 2 along with the Wahoo TICKR on a Cycleops Fluid 2 trainer since October 2019 without any major connectivity issues – just the odd minor Bluetooth pairing issue easily resolved by turning Bluetooth on and off. I use an iPhone XR to connect all three devices via the Companion App.
As of this week, I can no longer connect the Speed Sensor 2 to Zwift via the Companion App. The TICKR and Cadence Sensor both connect but the Speed Sensor displays “No Signal”. If I don’t use the Companion App, and only connect through the Apple TV, I can connect the Speed Sensor and one other device (either Cadence or HR) but not both obviously because Apple TV only allows two Bluetooth connections. My iPhone is able to connect with all three devices via Bluetooth at the same time and batteries have been replaced in all three recently.
Again, not sure what has changed recently to cause this issue – possible update with the Companion App?
Any suggestions/help much appreciated. Would be great to be able to connect all three devices again like I have been!