I use PlayOn and WMP as media severs, up until last week (before the 3.56 update) my PS3 slim stopped seeing the media servers on the network. I updated to 3.56, same issue. I completed a factory restore, same issue. Other devices on my network see my media servers just fine.
The network stats say Media Server is available, it is enabled and I even tried to toggle it on/off. I can scan for media servers but it finds nothing. uPnP is enabled on the network, and it worked up until last week.
Unsure what is going on here. Also a USB thumb drive was unable to playback media or pictures as well, but I was able to upgrade with the 3.56 OFW just fine yesterday.
DVD/BR playback is fine, and all my retail games play fine.
Not sure what could be the issue here.