Zwift connection to Neo Bike Plus is unstable.

I'm not having any connection issue between the Garmin/Tacx app and the Neo Bike Plus. 

However, connecting with Zwift has problems.  During a 72 minute workout I lost connection 3 times with Zwift.  I've tried both Bluetooth and ANT for all sensors in as many combinations I could think of.  I've also tried changing HRMs - Polare H9 and Garmin 010-12883-00 HRM-Dual Heart Rate Monitor.  Anybody know what the trick is to staying connected to Zwift?