Samsung Galaxy S7 Edge - Same issue. Was working fine for days. Shut down game normally, rebooted phone, tried to run again and now it will not start.
Note: installing block launcher and launching the game from there works, but still doesn't work when launching game directly.
I was able to resolve with, possibly, the date change. Here's, roughly, what I did.
Manually set date back a month or so...
Disable all data (Wifi, Cellular)
Launch Game
Either it works, or you get License error
If license error
Uninstall Game
Set Time to Automatic
Enable Wifi
Enter Play Store
Download Game
WHILE GAME IS DOWNLOADING - leave play store
Set date to Manual and backward a month
Wait for Install to finish (icon shows up)
Install finished
Disable Data (Wifi, Cellular)
Launch Game
Get License Error, Again (don't worry)
Enable Data (Wifi)
Launch Game, if works, great! If license error:
Set Time to Automatic
Launch Game, should work, if not, try Block Launcher app from play store.