Wow, this just started happening this evening, like a timed event from the PlayStore. It appears to impact EVERY Android Device running the new version 11.0.50. I think it has to do with the new requirement to access "Phone State".
In response, we just now released 11.0.57 to the PlayStore, which does not require "Phone State" access, and seems to fix this Lock-out for all who have tested it.
Please get this latest 11.0.57 Release from the PlayStore ASAP, and it should restore functionality for you.
(You'll know it's 11.0.57 if you check "What's New" and is shows "Last Updated, Dec 30th".)
As the PlayStore takes a while to rollout to everyone, it might not show up for you in the PlayStore until tomorrow morning (Dec 31st).
If you are in a big hurry, you can instead get this new release from our website.
http://www.iflygps.com/AndroidAPK