Mqqt failed to install

Hi there,

I’m trying to install the mqtt service via the add-ons within the hassio settings page, but it won’t install.
Other add-ons work fine.
I’m getting the following message in supervisor logs:

ERROR (SyncWorker_2) [hassio.docker.interface] Can't install homeassistant/armhf-addon-mosquitto:4 -> 500 Server Error: Internal Server Error ("readlink /var/lib/docker/overlay2: invalid argument").

Any clue what’s going wrong ?