Since you have a Galaxy S7 Edge, you should not need the app. The functionality is built into the device. I use it myself, and I find it much better than having an app. If you go into your device settings, you will have a new option below Advance Features called Multi-line settings. You manage your DIGITs here, which integrates directly with the native device software. You can then delete the app so it shouldn't interfere with your Grasshopper app any further.
If for some reason you do not see the multi-line settings in the device, please reboot the device and then follow these steps (found hereUse DIGITS on a phone or tablet)!
Use DIGITS on T-Mobile branded Samsung devices
DIGITS is built into the following T-Mobile branded Samsung devices:
- Galaxy S6, Galaxy S6 Edge, Galaxy S6 Edge+
- Note 5
- Galaxy S7, Galaxy S7 edge
To use DIGITS on one of these devices, make sure that you have the latest version of the device software by tapping Settings > About device > Download updates manually. After you've updated to the latest device software, enable DIGITS by tapping Settings > Multi-line Settings and logging in with your T-Mobile ID and password.