I have experienced an issue if my phone OS grabs focus from Zwift - e.g accidentally open task manager via swipe up, or asks for permission to store a photo -
Then the watts display goes to “-- W” and it’s like the Bluetooth stack connection is disrupted and wont resume. Disable and re-enable phone BT doesn’t fully work, nor reset of the trainer. As the trainer might then start showing in pairing menu after messing around, but then after every pairing attempt quickly goes to Not Connected without a single watt being sent. Briefly “0 W” might show then back to “-- W”. Even though the Bluetooth HRM pairs ok and starts reading again. Trainer resistance also goes to very low. Only solution has been to end ride, quit out and restart app. My phone is a Meizu 15, Android 7.1.1. My trainer is a Tacx Neo. My HRM is a Magene MHR10.