When trying to access the market place, it always says could not connect.

I made a world with lot's of command blocks, and when I die I can't see my hot-bar, and if i die again the game freezes.

When I try to join a server and it immediately says "could not connect" it takes 30 or more seconds to load and go back to the main menu.

When my friend is typing in chat, everything in the game freezes other than my movement.