Help me to solve server's problem

1.My server can't use itemframes when i put on the wall it doesn't show anything.

2.I can nethier see the messenge on chat.My friends and I can type on the chat but the chat is empty.

3.I can't see player in server but we are in the same place.We didn't /vanish and use the invisible posion.

I wish all of these problem can be solved.