Sorry, didn’t read your attached klippy.log and got you wrong with the title.
7260 serial = /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0
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7325 mcu 'mcu': Unable to open serial port: [Errno 13] could not open port /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0: [Errno 13] Permission denied: '/dev/serial/by-id/usb-1a86_USB_Serial-if00-port0'
See Sineos perfect How-To Trouble-Shoot.