Patch of AES required a reboot. After reboot, our application server was unable to re-connnect getting the error:
System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it

we saw a short period of time outs as expected during the reboot:
System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

Reboot of application server successfully returned function to normal.

any thoughts on why are new connection is not working, requiring a reboot?

The "...target machine actively refused it" error usually indicates that the port (4721 or 4722) is not accepting connections. Usually I see it if I try to connect to 4721 before enabling it using the AES Web Interface. maybe the DMCC service had not fully initialized when you tried to connect.

Martin