You may find if you change the settings in Syncthing or forget your password and the app no longer loads you need to reinstall it 

while doing this some times the App config is not removed so on reinstall you have the same issue 

the fix is simple here are a few ways to fix it 

Uninstall the app 

1) on rutorrent go to file manger at the bottom and click to .config folder and right click delete the Syncthing folder and reinstall the app 

2) Via ftp log in to your ftp in the address bar at the top type .config then it will take you to this folder and delete the Syncthing folder  and then install the app again

3) via ssh login go to .config and then do ' rm -r syncthing '  then reinstall 

all ways you just need to delete the Syncthing folder from .config and then install the app and it will then be back to default settings