I'm getting the same thing since yesterday (on both my phone and laptop too)! Funnily enough this thread is the only thread I can reply to!
Every other thread gives me the same message.
It's not that posts are being moderated in my case, it's not actually allowing me to write a reply. This message comes on upon clicking on the "post reply" button. It also says that my PM box is full even though it's not. lol