DLO server name and its IP address are not registered in hosts file.

1. Open “Terminal” on Mac.

2. Run "sudo vi /etc/hosts". (Password might be required.)
 
3. Add "IP address of your DLO server name" and "DLO server name." in hosts
 
For instance, if it is 192.168.1.1 and dlo80server, add below in /etc/hosts.
192.168.1.1  dlo80server
 
4. Save the hosts file.
5. Open DLO destktop agent on Mac.
 
If the issue is not gone, please run the commands below, in a “Terminal” window, to confirm whether the MAC can connect to the TCP port of the SQL server (Port 1433 by default).
 
Example: If the SQL server uses default Port 1433,
      “telnet 1433”
      “telnet 1433”

If MAC cannot connect to the TCP port of the SQL server. please refer to the article 100032461 .

"Unable to connect to Media Server." appears on MAC Agent. (See Figure 1)

Figure 1