How to fix this error "An error occurred while fetching Certbot snap plugins: make sure the snapd service is running."

full error message

An error occurred while fetching Certbot snap plugins: make sure the snapd service is running.
An unexpected error occurred:
requests.exceptions.ConnectionError: ('Connection aborted.', ConnectionRefusedError(111, 'Connection refused'))

just reinstall snapd or restart snapd service.

apt-get install snapd
systemctl restart snapd.service