These black shadow lines appears on certain edge loops, and I am unable to get rid off them. Is it a common mistake on my end and I can fix it easily, or do I have to redo those areas?
This tripped me and many others up as well. I thought something was completely messed up with my model and I redid it twice until I figured that out. Yeah it is totally the Normals. Shift + N to recalculate/flip normals