Why won't my filament feed through the extruder anymore?
I figured out the issue. I think I was shoving it in the wrong hole.

I took apart my extruder component. There's a good video on it here.
But basically, you just have to loosen the two bottom screws on the side fan like this:


I checked everything out first. I cleaned the extruder head with the included pin. I also shoved the filament through the heated area and filament came out ok.


But then I discovered the filament could go in the wrong way sometimes through the extruder.

This is the correct way for the filament to go through. It should come out of that plastic hole.


But once in awhile, I accidentally pushed the filament through this way.


If the filament was bent and I pushed the lever too hard, it would often find its way down the wrong path.
So I played around with how much force I should be holding down the  lever and how hard I should be pushing the filament through.

I don't know if other 3D printer extruder feeders are designed this way, but seems error prone. Or maybe it's just me.