Lights Not Working on Pre-lit Tree?

I removed the non replaceable fuse bulb and white base with very little difficulty. I replaced the fuse bulb with one of the working regular bulbs back in the white base, folded the wires up like normal and placed it in the string light socket. Should have worked, but light bulb is unlit as still are the six branches. What could be my problem? Help please, I am getting frustrated!

By Jan R.