Likely the front and/or rear shift linkage bushings are damaged or missing.
A damaged/missing front shift linkage bushing will create too much slop in the linkage and prevent the NSS from completing the starter circuit.
You don't need a special tool to press in a new shifter bushing (MB Part number 1159920310)
Just soak the bushing in warm water for a few minutes to soften it a little.
Make a press using a bolt, a nut, the appropriately sized socket, and few large washers.
Transmission Shifter Bushing Tool Helper. - Mercedes-Benz Forum
BTDT.
