We see this come through support once in awhile and I wanted to use this blog post to try and explain what can be happening to cause this issue.
First, some quick background. Even though Maya is rendering locally it still depends on these sockets for communication. Maya will simply use this communication channel like a two radio communication between the batch render application and Maya. So what happens in a network environment is that Maya will actually routes itself through the network back to your machine.
This is why you must to make sure that the firewall settings are allowing the mayabatch process through regardless of being on a network or not. The firewall is the most simplest solution but we do run into atleast another two scenarios in support.
1. You may also have two Maya session loaded, maybe a background render that has not completed and is locking the port. To fix this either wait till the process is completed for submitting another bacth or check your tasks and kill off the rogue mayabatch.
2. The other is a DNS issue, we find this generally on the Mac side of things. We have seen this after a system has picked up a new IP from the server but the DNS has not refreshed itself and is now pointing to another machine. Since the machine is loaded on the network it has a difficult time finding itself. Generally this issues fixes itself after a few hours.
If that does not happen to work out, you can try flushing the DNS cache on your local machine manually.
In a Mac OS terminal simply run the following. You may need to reboot afterwards.
sudo dscacheutil -flushcache
Hope this helps!