I have a problem with friends on my network

Hello,
my network connection is fine and so is my friend , however when we try to join in on a game we cannot, with a screen continually saying that the game is no longer available, we have tried this even on a private game with just the two of us and we live in the same time zone , is this a problem with the playstation network or is it something else , we are also not the only people who have a problem with this any help on this matter would be greatly appreactied , thank you