Side brush falling off

It seems my side brush keeps falling off and i constantly have to keep screwing it back on. The hole you screw into looks like it may be rusty but its hard to tell, its small.

The threads that you're screwing into may be stripped. Some people might suggest using glue, the problem is when you need to replace the side brush the next time, it could be really difficult to get off. You may want to contact support for advice.