I've been seeing this error in the log:
ERROR : Failed to open Web GUI in browser: exec: "xdg-open": executable file not found in $PATH. Manually access it at:
I only have a debian server without GUI. This is normal?
That is rclone trying to open your web browser pointing at the GUI because you used the --rc-web-gui flag. If you don't want it to attempt to open a web browser then use
--rc-web-gui-no-open-browser Don't open the browser automatically