I try to type sudo apt upgrade. After that it gives me an error:
E: Could not read response to hello message from hook [ ! -f /usr/lib/ubuntu-advantage/apt-esm-json-hook ] || /usr/lib/ubuntu-advantage/apt-esm-json-hook || true: SuccessE: Could not read response to hello message from hook [ ! -f /usr/lib/ubuntu-advantage/apt-esm-json-hook ] || /usr/lib/ubuntu-advantage/apt-esm-json-hook || true: Success