Upload button disappeared! - Solved

What is the problem?
my file upload buttons and controls disappeared after the first print?

What did you already try to solve it?

started and stopped the server

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)

Monoprice Delta mini

What am I missing?

Thanks for the help!

I guess it logged me out but still let me connect?

So it's solved, but I'm still confused.