In regards to the follow error I believe I know the solution:
The issue is in the /etc/hosts file.
On your MangoES SSH in and run "sudo nano /etc/hosts"
Your file should look like this:
The last line if the part to note. This needs to match what the host name is of your MangoES. There is a bug in the MangoES configuration module where if you change the Hostname there the hosts file does not get updated. In my tests getting the hostname correct in the hosts file will resolve this issue.
Please let me know if that works