A fatal error occurred: Could not open COM4, the port is busy or doesn't exist.
(could not open port 'COM4': PermissionError(13, 'Access is denied.', None, 5))

 

Hi cos,
Have you checked on the PC's 'Device Manager' menu option, that COM4 is available or in use.?
E

 

most USB things are not handling detection well. if the COM port is created when USB device is connected, you may have to unplug it and then plug it back in. this may be needed if PC was rebooting for some reason (updates?). at any rate, device manager must show it or you can't use it. some devices change COM port when connected to a different USB port. so maybe it is there but no longer as COM4. if it is not showing at all, you need to check drivers or USB cable or hub (whatever is between ESP and PC). if the COM port exists but cannot be used, chances are that some process still has hold of it. sifting through processes is challenging so usually the simplest solution is to reboot and try again. that should end any lingering process and free resources.

 

there is the com4

 

i'm not using a USB hub

 

hoh! hoh! i fixed it by changing the upload rate to 115200
thanks guys