Smart Switches aren’t available outside network?

Hi,

I have installed (2) HS220's, (1) KP200 and (2) EP10 in my home and they work great. All devices here are available through the app on my home WiFi network, but the HS220's drop when I am away from home -

How can I get the HS220's ('Bathroom Light Switch' & 'Workout Room Switch') available for access outside my WiFi network? They currently work fine on this home WiFi, but are not accessible outside that? 🤔