BBM shows a Red X while sending from BB to iPhone or Android

So what does it mean when a Red X is displaying when you send someone a BBM message? This can happen if you send from iPhone to Android, or Android to BB or between any BBM smartphone device.
The Red X is placed right beside the sent message. You might already know that the Red X means your message was not delivered.
Things that can trigger the RED X when you try to contact people:
1. They have not activated their internet, so they don’t have access to BBM…
2. They no longer have a valid BlackBerry Data plan, or haven’t paid their bill, or renewed the service…
3. The Red X mark means their BIS isn’t activated/active
4. The recipient could have deleted you from their BBM contacts.