Possible Solution:
Wait 60 seconds before trying to connect again.
The software is behaving correctly. The server sees no name and and no password as a bad connection and waits for a timeout. The server waits 1 second, 2 seconds, 4 seconds, and so forth, to 60 seconds before rejecting a connection. It is during this time that the number of connected users can build up to the maximum. The number will drop back down after no more than 60 seconds from the time of the first connection. You will not be allowed to quit the Mac OS Server Admin Agent until the last connection times out.