Tape on 5V - not working on Ender 5 Plus

What is the problem?
I get "too many consecutive timeouts" when I don't supply 5V via USB.
Yes my printers PSU is on and set to 230V.

Additional information about your setup
I have tested this for serveral prints now and it definitly only happens when I don't supply 5V via USB. The printer works fine under other circumstances aka printing from an SDcard/generally printing via USB. So no buggy printer firmware or pi.

Reason for this post
I could not find any mentioning of an Ender 5/... Plus getting timeout errors because of this, so can other people confirm this or is it just me getting unlucky?

This is what I get on the Robo 3D controller board, for what it's worth. Sometimes it works, sometimes it doesn't.