Crankshaft ignition sensor

  mercedes/m-class/1998-2005

ML 320. 2001 Mercedes.
I purchased my 1st sensor. The first one was slightly different so I couldn't plug it in. I put the old one in and got the car started. So today I received my new sensor (2nd one) and plugged it in. The car started so I shut it off. After tightening the screw, I tried starting it again. No dice. Won't even turn over. I thought if may be the battery so I tried jump starting. No dice. It just clicks. Could the next thing be the alternator?

PS. I found utube videos for the crankshaft sensor. So im trying to wind down possible solutions.

What else does anyone recommend?

8