ANT dongle stopped working on iMac


I run zwift on a imac i5 2.7GHz with 16GB RAM and a ANT dongle (2016 model) that connects to my Tacx Flux. All worked well until today when I was no longer able to connect Zwift via ANT to my Tacx. I ended up connecting via bluetooth and rode without hear rate and cadence monitor who need ANT connection. Following actions did not help: Restarting Zwift, rebooting iMac incl SMC reset, changing dongle to another USB port. I did not run any iOS updates recently either (I run OS X ver 10.9.5). Funnily enough, when I plug the dongle into a windows computer it connects Zwift to my Tacx. 

Any advice how to make the ANT dongle work again on my Mac?