Check transaction log on your SQL server.
I had same problem and after shrink transaction log, everything is OK.
I also have separate Uniprint and DB servers. I manually control my Windows Updates on these boxes so I know there isn't any unexpected restarts. On my Uniprint server I have a scheduled task to manually restarts the server early every morning regardless. I found out that when I did this (at least with Uniprint 7.2) the system had less issues. I decided to keep the same task in place even though I'm at 8.2 now... although 8.2 seems to be a lot more stable that 7.2 was. So you might just want to have a scheduled task to just restart those services that are giving you problems....
After cleaning transaction log file, server was OK for few hours and than started connecting/ disconnecting again.
Very strange situation! Network tested, server to server connection tested- everything OK. But PharosUniProxy looses connection!
Did somebody have this problem?