Message to friend won't send

Have written a message to someone who is a friend but it won't go. What must I do please?

Hi Libby, if it's on SFN then I think you need to add the member as a friend and they need to accept you as a friend. You can include a quick message in the invite but it's only short. Once your friend has accepted you then you should be able to send messages without problems. If you know that your friend has accepted your friend invite but you still can't send messages to them on SFN then please do come back on here and let us know.