Im having the same issue as Lincoln however instead of going and buying a whole new HR monitor I bought an Anself ANT + device to connect my Garmin Tri HR monitor to Zwift. However Zwift is not picking up the Ant+ device.
I have MacBook pro laptop, TacX Vortex trainer , Garmin Fenix 5 watch, the Ant+ device and the Garmin HR monitor.
Thanks mate for your quick response. The “phone” signal is just the bluetooth connecting my trainer through the Zwift companion app on my iPhone 8 so I cant turn the phone off. I’ve read that the bluetooth through the companion app can connect the trainer (and therefore power/cadence/speed) while the Ant+ connects the HR monitor … but maybe not?
And regarding the Ant+ connecting to multiple software programs. i did close down /quit Garmin Express but alas that hasn’t done the trick either. i’m stumped.