Garmin 6 pro with Mio ant+ heart belt

Hi,

Just moved from a fenix 3hr to a fenix 6pro. With my 3hr I used a heart rate belt from Mio, SHRM1g ANT+ compatible, and the setup worked smoothly. For some reason I'm not able to connect the belt with my fenix 6 pro?

Any thoughts or ideas? Is the new garmin more restrictive? 

Thanks! Co