Cura slicing gaps in perimeter walls

[Phill1337]

Hello everyone,

i am new to 3d printing and i have an issue with sliceing a pen for sanding paper. The primeter has weired gaps. I toyed around with various wall, infill and mesh fixes but nothing seems to help. Before i noticed i tried to print it and the print even stoppes at seemingly random positions :/
I attatched the gcode. I would be very gratefull if someone could have a look. Thanks.

Regards,
Phillip