I am new to the community I have just configured a SmartThings hub and Schlage smart lock.
I followed this procedure to add the Smart-Lock-Guest-Access “Card”
and all was working well, but at some point it lost connection and today I observed error “can’t connect to device. Check device and try again“ on both the hub and lock icons on the new app.
I tried power-cycling iPhone, then ST hub, then router…ST hub light went green and I noticed i got some messages from manually locking etc. but the Smart-Lock-Guest-Access “Card” was still gone so could not remotely control. I could not even use the 'Report a problem" from the app-help.
I called support and they had me uninstall/reinstall/log back in and at that point everything came up. I can now see the SLGA card and all shows connected.
ST hub V3.
Schlage: Camelot touch screen
Hope this helps others.