Hi all,
We are aware of the issue and investigating it. Our first guess is that it might be related to the latest Google Play Services update (which is automatically updated in the background) - seeing the majority of users encountering this issue arose around the same time.
A temporary workaround is to disable the SIM pin code in Settings > Security. Of course, make sure you have a device pin/pattern set up. Once we have a fix ready, make sure to enable the SIM card pincode again 
Temporary workaround #2: Go to Settings > Location > and set it to “Battery saving”.
Cheers,
Rick
The Product team