It can be a nightmare when you see the 503 Service Unavailable on Fiery programs such as the Fiery Command WorkStation. You will often see the error message shown below when attempting to configure the device in the Device Center or by accessing the server directly via the IP Address in the browser at port 80.
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
There is a very high chance that you are utilizing a Windows-based Fiery. If so, please check to see if the Windows Firewall is enabled on the Fiery. Since the Fiery server has a firewall, antivirus firewalls are not generally required.
Fiery will need to access the following ports 161 and 162 for SNMP and WebTools so be sure to check with the network administrator to see if they have restricted and have them unblocked.
Antivirus programs may accidentally quarantine or block resources so the utmost caution must be used when utilizing an Antivirus program in conjunction with EFI software.
As the error message stated, maintenance could be in progress. Take a look in the Device Center to see what is going on. While there, check to see your current API version. If there is an update, try and push it through. Once correctly installed, you will be able to access the server at port 80 in the web browser and via your Fiery software.