Wouldn't you think that this would affect all users? I have plenty of other vm to email including myself that receive vm's just fine. I will reboot the server. Not sure what MLS config means but on the NuPoint under email settings we do have a server to use for outbound SMTP configured.
Depends on the destination email... The server may be allowed to relay to certain addresses or domains, but not others.
For example... john@mycompany.com may work fine, but john123@gmail.com or mark@differentcompany.com may fail since the server isn't allowing external relay to those addresses.
But either way, since your using an external SMTP server the MSL server is handing it off to that server and it's returning the Unable to Relay message.