Merged plotted layers

[retiredfeline]

Probably same issue as this report:

Submitting gerber files

I’m new to this. I created a 4 layer PCB in KiCad 7.02, created all the gerber files and the drill files. Packed them in a zip file and submitted it to PCBWay. They rejected the file with reason “All the layers are duplicated”. Can anyone explain how this can happen? Thanks, Russ