Printer wont connect, Win 10

Just installed Octoprint on my Surface Pro which is running Win 10 Pro, 64 bit. Created the virtual environment, launchd Octoprint with the "Octoprint serve" command.

I then went through the connection process in Ultimaker Cura, say the option for "Desktop-93...tcp.local'' and clicked "Open in Browser."

However, I cant seem to get the printer to connect and CMD is displaying that " Failed to connect: Port COM4 is busy or does not exist."

Already tried launch a reboot, launching it in safe mode and changing the serial port to "Auto."

System info:

2023-01-07 13:23:40,933 - octoprint.server.util.sockjs - INFO - New connection from client: ::1

2023-01-07 13:23:42,157 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:23:42,161 - octoprint.server.api - INFO - Actively logging in user Decter8425 from ::1

2023-01-07 13:23:42,373 - octoprint.server.util.flask - INFO - Passively logging in user Decter8425 from ::1

2023-01-07 13:23:42,373 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:23:42,739 - octoprint.server.util.sockjs - INFO - Client connection closed: ::1

2023-01-07 13:23:44,524 - octoprint.server.util.sockjs - INFO - New connection from client: ::1

2023-01-07 13:23:44,567 - octoprint.server.util.flask - INFO - Passively logging in user Decter8425 from ::1

2023-01-07 13:23:44,567 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:23:45,893 - octoprint.server.util.sockjs - INFO - User Decter8425 logged in on the socket from client ::1

2023-01-07 13:23:54,168 - octoprint.util.comm - INFO - Changing monitoring state from "Offline" to "Detecting serial connection"

2023-01-07 13:23:54,172 - octoprint.util.comm - INFO - Serial detection: Performing autodetection with 7 port/baudrate candidates: COM4@115200, COM4@250000, COM4@230400, COM4@57600, COM4@38400, COM4@19200, COM4@9600

2023-01-07 13:23:54,172 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 115200

2023-01-07 13:23:54,172 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 115200

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 115200, skipping

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 250000

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 250000

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 250000, skipping

2023-01-07 13:23:54,180 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 230400

2023-01-07 13:23:54,189 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 230400

2023-01-07 13:23:54,190 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,191 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 230400, skipping

2023-01-07 13:23:54,191 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 57600

2023-01-07 13:23:54,192 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 57600

2023-01-07 13:23:54,194 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,195 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 57600, skipping

2023-01-07 13:23:54,195 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 38400

2023-01-07 13:23:54,196 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 38400

2023-01-07 13:23:54,199 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,199 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 38400, skipping

2023-01-07 13:23:54,200 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 19200

2023-01-07 13:23:54,201 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 19200

2023-01-07 13:23:54,202 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,202 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 19200, skipping

2023-01-07 13:23:54,203 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 9600

2023-01-07 13:23:54,204 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 9600

2023-01-07 13:23:54,205 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:23:54,206 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 9600, skipping

2023-01-07 13:23:54,206 - octoprint.util.comm - INFO - Changing monitoring state from "Detecting serial connection" to "Error"

2023-01-07 13:23:54,207 - octoprint.util.comm - INFO - Changing monitoring state from "Error" to "Offline after error"

2023-01-07 13:23:54,218 - octoprint.plugins.action_command_notification - INFO - Notifications cleared

2023-01-07 13:24:37,646 - octoprint.server.util.flask - INFO - Passively logging in user Decter8425 from 192.168.86.86

2023-01-07 13:24:37,646 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:24:43,767 - octoprint.server.util.sockjs - INFO - New connection from client: 192.168.86.86

2023-01-07 13:24:47,673 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:24:47,674 - octoprint.server.api - INFO - Actively logging in user Decter8425 from 192.168.86.86

2023-01-07 13:24:47,869 - octoprint.server.util.flask - INFO - Passively logging in user Decter8425 from 192.168.86.86

2023-01-07 13:24:47,871 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:24:48,247 - octoprint.server.util.sockjs - INFO - Client connection closed: 192.168.86.86

2023-01-07 13:24:49,354 - octoprint.server.util.sockjs - INFO - Client connection closed: ::1

2023-01-07 13:24:50,241 - octoprint.server.util.sockjs - INFO - New connection from client: 192.168.86.86

2023-01-07 13:24:50,293 - octoprint.server.util.flask - INFO - Passively logging in user Decter8425 from 192.168.86.86

2023-01-07 13:24:50,293 - octoprint.access.users - INFO - Logged in user: Decter8425

2023-01-07 13:24:51,954 - octoprint.server.util.sockjs - INFO - User Decter8425 logged in on the socket from client 192.168.86.86

2023-01-07 13:24:59,828 - octoprint.util.comm - INFO - Changing monitoring state from "Offline" to "Detecting serial connection"

2023-01-07 13:24:59,836 - octoprint.util.comm - INFO - Serial detection: Performing autodetection with 7 port/baudrate candidates: COM4@115200, COM4@250000, COM4@230400, COM4@57600, COM4@38400, COM4@19200, COM4@9600

2023-01-07 13:24:59,836 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 115200

2023-01-07 13:24:59,836 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 115200

2023-01-07 13:24:59,844 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,844 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 115200, skipping

2023-01-07 13:24:59,852 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 250000

2023-01-07 13:24:59,854 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 250000

2023-01-07 13:24:59,856 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,857 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 250000, skipping

2023-01-07 13:24:59,857 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 230400

2023-01-07 13:24:59,857 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 230400

2023-01-07 13:24:59,858 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,858 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 230400, skipping

2023-01-07 13:24:59,858 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 57600

2023-01-07 13:24:59,859 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 57600

2023-01-07 13:24:59,860 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,861 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 57600, skipping

2023-01-07 13:24:59,861 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 38400

2023-01-07 13:24:59,862 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 38400

2023-01-07 13:24:59,864 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,865 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 38400, skipping

2023-01-07 13:24:59,865 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 19200

2023-01-07 13:24:59,866 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 19200

2023-01-07 13:24:59,868 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,868 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 19200, skipping

2023-01-07 13:24:59,868 - octoprint.util.comm - INFO - Serial detection: Trying port COM4, baudrate 9600

2023-01-07 13:24:59,871 - octoprint.util.comm - INFO - Connecting to port COM4, baudrate 9600

2023-01-07 13:24:59,874 - octoprint.util.comm - INFO - Failed to connect: Port COM4 is busy or does not exist

2023-01-07 13:24:59,874 - octoprint.util.comm - INFO - Serial detection: Could not open port COM4, baudrate 9600, skipping

2023-01-07 13:24:59,874 - octoprint.util.comm - INFO - Changing monitoring state from "Detecting serial connection" to "Error"

2023-01-07 13:24:59,876 - octoprint.util.comm - INFO - Changing monitoring state from "Error" to "Offline after error"

2023-01-07 13:24:59,892 - octoprint.plugins.action_command_notification - INFO - Notifications cleared

WRITE HERE

Setup:
Printer: CR10V3
Firmware: 5.2.1 (Cura)
Version: 3.10.5
OS: Win 10 Pro, 64 bit.
Browser: Crhome

Any help would be greatly appreciated!!

If you close Cura and then try again to connect, is it successful?

Cura will automatically hold any serial ports it finds by default, meaning you can't access them in OctoPrint.

Sadly, no. I've tried several times.

Resolved, another user on the Discord helped.

I had Cura running when I was trying to connect. As soon as I turned it off, it worked great.

Did I miss something?

1 Like

Lol, no but I did. I misunderstood the original advice and simply restarting everything, leaving Cura running while trying to connect to the server.

All I needed to do was turn Cura off, set up/connect to the server and then turn Cura back on.