PS4 messages are not displayed?

I have had a problem for a few days now. When I go to Messages on my PS4, I see "All" "Favorites" and "Send messages with the mobile app" on the right where the messages should appear but is only an empty one Field and if a message is sent to me and I would like to look at it via the PS button there's "please wait" and shortly afterwards an error message is displayed to me that "an error has occurred (CE-33866-6) Maybe someone can give me help

There's certainly a way to enter this error code on a PlayStation ™ website to see what you can do just google something like "Playstation error code meaning"

Couldn't find anything about this error code