Facebook Help PLEASE?

[MOJO JOJO]

I unblocked my friend on facebook and he added me again, I accepted and I sent a message but this popped up "This message was created automatically by Facebook.

Based on the privacy settings of the person you're trying to contact, this message could not be delivered. Try sending them a Friend Request, wait until they accept it, and then try sending your message again."

I don't get it?! We're friends again and I'm trying to send him a message! Why can't I?
Help really needed asap thanks

[Alexsus]

'Try sending them a Friend Request, wait until they accept it.' did you try doing that?