You might have been struck by the spam filter. Usually, if you mentioned too many people in your post, or tried to post the same text twice in a short period of time, your post will not be delivered. ...
spam
Other players don’t seem to receive my private messages, what should I do?
You need to be friends with someone in order for them to be notified of your private messages. Otherwise, your message will be delivered but they may not be aware of it, as it’s stored in a spam sec...