While installing official addons, many shown in grey and apparently not available

Hello, I searched in the entire forum, altough there are similar issues I could’t resolve it yet.
I can’t install many of the official add-ons on HA.

As you can see some of them are grey, with a red line on the top.

I have Hassio running on Docker, on a standalone Debian 10 box (i5, 8gb Ram, 110Gb free on the hdd).
Different DNS were used, PiHole, Google and Opendns.

The system is updated to the latest version, and logs not showing any red entry.
I was able to install without any problem other addons like InfluxDB, Mosquitto etc, when it was the turn of grafana this is the message I get:

On the Grafana documentations there’s no limitation theoretically affecting its installation on my system.
Any idea about how to fix this? any help is appreciated.