You may need to edit your /boot/config.txt file and add a line to allow max power to the USB. If you dont have the line
max_usb_current=1
in the /boot/config.txt then add it and reboot.
You can try manually following this tutorial: https://community.openhab.org/t/raspi-2-move-system-root-to-usb-ssd/15243?u=h102