Ender 3 Max not connecting to OctoPrint

What is the problem?
OctoPrint doesn't detect the printer

What did you already try to solve it?
I am a new user and I have OctoPrint running on my windows pc. I know it isn't conventional, but I already have my pc running 24/7 so I didn't think it made sense for me to buy a Pi for this situation. OctoPrint is running fine, I have my webcam hooked up and I even enabled the Virtual printer to troubleshoot and confirm that it was all setup correctly. The only solution I've been able to find for this issue is "try another USB cable", I've tried at least 5, and I know the cables all worked because I can hear the device connected sound on my pc whenever I plug the printer in. I've updated the OS, as well as updated OctoPrint through the web interface. I have no idea what the solution is.

Logs (syslog, dmesg, ... no logs, no support)
Changing monitoring state from "Offline" to "Detecting serial connection"
Performing autodetection with 7 port/baudrate candidates: COM3@115200, COM3@250000, COM3@230400, COM3@57600, COM3@38400, COM3@19200, COM3@9600
Trying port COM3, baudrate 115200
Connecting to port COM3, baudrate 115200
Unexpected error while connecting to serial port COM3, baudrate 115200 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 115200, skipping
Trying port COM3, baudrate 250000
Connecting to port COM3, baudrate 250000
Unexpected error while connecting to serial port COM3, baudrate 250000 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 250000, skipping
Trying port COM3, baudrate 230400
Connecting to port COM3, baudrate 230400
Unexpected error while connecting to serial port COM3, baudrate 230400 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 230400, skipping
Trying port COM3, baudrate 57600
Connecting to port COM3, baudrate 57600
Unexpected error while connecting to serial port COM3, baudrate 57600 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 57600, skipping
Trying port COM3, baudrate 38400
Connecting to port COM3, baudrate 38400
Unexpected error while connecting to serial port COM3, baudrate 38400 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 38400, skipping
Trying port COM3, baudrate 19200
Connecting to port COM3, baudrate 19200
Unexpected error while connecting to serial port COM3, baudrate 19200 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 19200, skipping
Trying port COM3, baudrate 9600
Connecting to port COM3, baudrate 9600
Unexpected error while connecting to serial port COM3, baudrate 9600 from hook default: SerialException: 'could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)' @ comm.py:_open_serial:3775
Could not open port COM3, baudrate 9600, skipping
Changing monitoring state from "Detecting serial connection" to "Error"
Changing monitoring state from "Error" to "Offline after error"

Additional information about your network (Hardware you are trying to connect to, hardware you are trying to connect from, router, access point, used operating systems, ...)
OctoPrint version: 1.7.0
pip version: 21.3
Printer: Creality Ender 3 MAX w/ CR touch (same as BL touch)
Firmware: Marlin Ver 1.0.1.6
OS: Windows 10

"Access Denied" hints at the port already being in use. Got a slicer open like Cura or Simplify3d? They like to grab a hold of any connected 3d printers to control then themselves...

Ok, I just got home and COM3 had disappeared. I closed Cura, that changed nothing. I then found a reddit thread suggesting a USB to Serial port driver so I installed that, it has mostly fixed my problems. The only issue now is that I have a "Warning: Firmware Broken" message on OctoPrint. Is that an issue and how can I fix that?
I also have some weird bug now regarding the temperature graphs. I set the tool temp to 200 and my bed temp to 60 through OctoPrint (my printer understood that and heated to the correct temp), but as you can see OctoPrint isn't showing that.

Nevermind, I followed the "Learn more" instructions and all of my problems are solved!
If anyone else has the same issue as me try: This reddit thread
The comment from u/CasualDrives (while very sketchy looking) solved my issue

Thanks for the help!

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.