In general terms, there are two possibilities for getting it blocked, in this most possible order:
1.- There could be a firewall running, if so it should be disconnected: going to "System Preferences" -> "Security and Privacy" -> "Firewall"
2.- If not, you could have a hostName problem. In order to figure out if this is the case, just go to a Terminal and type:
And with whatever hostname you get, then type: ping <what hostName it returned>
If it returns:
a) cannot resolve hostname: Unknown host
Then you have a hostname conflict: the hostname you have configured is not good, and you must go to "System Preferences"->"Sharing". There under "Computer Name" you will see a string that says:
"Computers on your local network can access your computer at:
So, go to Terminal and type:
sudo scutil --set HostName <computer_Name>.local
Afterthat you can restart or go to re-read. It should work. If it doesn't work, we will need a deeper information from your system so click on the button "Diagnostics" in the RLM UI, (in the button area below "Reread Restart Servers") and send the diagnose file to our Technical Support for a further exam.
b) if you get something similar to:
PING nacho.local (192.168.0.69): 56 data bytes
64 bytes from 192.168.0.69: icmp_seq=0 ttl=64 time=0.060 ms
64 bytes from 192.168.0.69: icmp_seq=1 ttl=64 time=0.073 ms
64 bytes from 192.168.0.69: icmp_seq=2 ttl=64 time=0.107 ms
(you can stop it with Ctrl+C)
In thiscasecontact our Technical Support and send us the information in the Diagnostics button on the RLM UI, (in the button area below "Reread Restart Servers") and send us the file.
A bit more information about how OSX handles host namescan be found in web siteslike this