Vertex K8400 - 2nd extruder is not loading filament

Hallo,

Wij hebben de Vertex K8400 in elkaar gezet.
Rechter extruder doet wat hij moet doen. Laad het filament.
Linker extruder heeft precies niet genoeg kracht om het filament te laden ?
Hoe kan dit ?

Mod edit (translated question to English)
We put the Vertex K8400 together. Right extruder does what he needs to do. Load the filament. Left Extruder does not have enough power to load the filament? How can this be?

Make sure the screw is not to tight.
3366

Make sure this screw is tight
3367