Using two printers - Archer C7 V4

Hi,

I want to use two printers on each usb port.
Port1 is working, Port2 does not recognize any plugged in usb device (usb led on routers back doesn't light up). Maybe there is a trick to use the second usb port as well.
Setup via https://openwrt.org/docs/guide-user/services/print_server/p910ndprinterserver

And yes, both printers are working properbly.

lsusb & packages:
image

OpenWrt 19.07.4 r11208-ce6496d796
TP-LINK Archer C7 V4

Regards
Philipp