I think I've figured out the issue. I use a powerline adapter to connect online and after switching to an outlet in another room, I'm finally able to create a room. Just a guess though. Do you use a powerline adapter @
SS-BDXCVII
About a month or so. After seeing all that you've tried, I'm starting to think it is our ps3 systems. Mine's is around 10 years old and makes a loud noise after it is on for a few minutes. How old is yours?
I have a similar issue. Can't create rooms, send match requests in Global, or play in ranked. The only thing available for me is joining a room in player match.