Goodreads Developers discussion

I'm one of my groups we play a game and we're out on to teams , we then send emails letting our team members know what books we picked for them to read even if we're not friends on goodreads, I was able to send three message to 3 of the team members but when I tried to send messages to the others I get the same message , person isn't accepting message, and in the past I was able to do so .is there a bug making it impossible for us to send messages to others. And when I go to add them as a friend and try to answer their questions I can't do that either