Forerunner955 Solar can't connect to BaseCamp

Hi everyone,

I would like to use the preinstalled TopoActiveMaps on my Garmin Forerunner955 Solar watch to plan some routes in BaseCamp. However, for one reason or another my watch is not showing up in BaseCamp upon connecting it to my Mac. It does show up in GarminExpress and I can use all of it features as usual. 

What could I be missing? 

Thanks for your help!

Best

Lennart