I have the same problem. If I turn developer mode on, I can't use the Jolla store anymore. Only fix seems to be to reset the device to factory settings. As a developer, a fix to this would be nice. Edit: Ah, there's a bug if one selects the dev updates. Workaround: http://elinux.org/Jolla#Avoid
The other half ambience is still not downloadable when pairing it with the phone. "There was a problem with the store" Edit: I can't download anything from the store. Seems that I ran into the same bug AGAIN. I am not willingly factory resetting my phone anymore. Android apps works ok, both store and installing.