The settings look good to me.
Can you please reboot the phone and see if starts to work?
Common reasons:
- The use of "memory optimizer" apps like Clean Master
- The use of "battery optimizer" apps
- Swiping the app "away" from Android's recent apps list
If none of the above applies, or doesn't help, please capture the issue in the app's debug log (see below).
Just enable the log with "raw data" enabled, and leave the app alone for 2-4 hours, then send me the log file (kmansoft / gmail).