edit
Case closed.
With no errors what so ever from the MM side, everything seemed to work normal. Either MM or the modules I tried did not resolve FQDN names… ! (MM is configured with two local DNS servers) I think this should be reported in some of the logs on MM… Nothing.
I figured it out when I did a lsof on my Grafana server and there were no connection from the MM there… Only my own pc… LOL
Well, back in business again after some hours troubleshooting… Probably learnt a thing or two also along the way.
I tried with another module capable of showing iframes. Same problem there. It refuses to show the content on the MM monitor only on a browser from another computer. There everythings shows up as normal.
Even removed all other modules sharing the same position as this one.
I am stuck…