Filament extrusion always stops at some point during print
Stringing?

The stringing is explained by your relatively low retraction settings, 1.5&nbsp;mm is not much for a Bowden setup. As do too high printing temperatures.

Stopping mid printing?

What you are experiencing is called clogging, the extruder cannot push the filament through the hotend and cause the grinding you report. Clogging mid printing is usually caused by insufficient cooling (for the temperature you print at) of the cold end (causing heat creep; slowly increasing temperature of the heat break), especially all-metal hotend assemblies are notoriously known for this problem. 

Your Bowden tube does make a lot of kinks, maybe you can improve the path of the Bowden tube. Also if you are concerned about the sharp filament intake angle, you could print a filament guide: