What is the problem?
Cooling fan is not turning on even thought the commands to do so are in the Gcode, and the fan works when you manually turn it on via the printer itself. Everything worked perfectly fine all day and just recently stopped working correctly.
What did you already try to solve it?
I have manually sent G106 commands via Octoprint cmd line, it did not even acknowledge that I sent the command, sent a G0 X command, it sent and received as normal.
I have taken the same gcode and loaded it via usb to my printer and it works as it should.
Have you tried running in safe mode and if so did it solve the issue?
Able to send the G106 command in safe mode fan engages with no issue.
serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support! Not log excerpts, complete logs.)
Additional information about your setup
OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
OctoPrint EZPi V2.0, Artillery Sidewinder X1, Marlin 1.19, windows