Does that mean it stops after some time or doesn't work anymore at all?
you have to add something to that command - like nano to open it in a text editor. (nano /var/log/webcamd.log)
I would suggest that you use WinSCP to connect to your pi an download the log file.
It looks like a file explorer.
Found video devices:
/dev/video10
/dev/video11
/dev/video12
/dev/video13
/dev/video14
/dev/video15
/dev/video16
config file='/boot/octopi.txt':USB device was not set in options, start MJPG-streamer with the first found video device: /dev/video10
/root/bin/webcamd: line 184: printf: 0x: invalid hex number
/root/bin/webcamd: line 184: printf: 0x: invalid hex number
<13>Dec 2 12:56:15 root: Starting USB webcam
Checking for VL805 (Raspberry Pi 4)...
It seems that you don't have VL805 (Raspberry Pi 4).
There should be no problems with USB (a.k.a. select() timeout)
Running ./mjpg_streamer -o output_http.so -w ./www-octopi -n --listen 127.0.0.1 -i input_uvc.so -r 640x480 -f 10 -d /dev/video10
MJPG Streamer Version: git rev: 5554f42c352ecfa7edaec6fc51e507afce605a34
i: Using V4L2 device.: /dev/video10
i: Desired Resolution: 640 x 480
i: Frames Per Second.: 10
i: Format............: JPEG
i: TV-Norm...........: DEFAULT
Error opening device /dev/video10: video capture not supported.
Init v4L2 failed !! exit fatal
i: init_VideoIn failed
Done bring up all configured video device
Goodbye...
Starting up webcamDaemon...
Starting up webcamDaemon...