Chat messaging "unable to send right now"

Recently i have not been able to message one of my friends in chat messaging. When i type in the message window and hit send, i get a red circle beside my sent message. No record of any messages are seen. This is the only person that i cannot msg with. All others I have no problem with. This problem is only on my Ipad. I can send messages on my Desktop computer with no problem. I have tried to reinstall facebook app but still have the problem. Please help.