I've been looking into the land.php file -> confirm_mnet_session and the firsts lines block the access if the host is not configured locally, so I presume I didn't understand how the community hub really works.
A Community hub is not an open hub where I can connect my site with no more actions from the community hub administrator, he always has to add the satellite site (peer), am I wrong?
This is not what I can read in the peers menu:
"You can choose to register all hosts that try to connect to you automatically. This means that a record will appear in your hosts list for any Moodle site that connects to you and requests your public key."
So what I can see is that if I set "Register all Hosts" in "server B" and later I add "server B" as a peer in "server A" (the process gets the public key and I configure the services) then in "server B" there is no record for "server A" in the mnet_host table. Is this the problem?