Why is the caller ID showing as unknown, blocked, withheld, or private for outbound calls?
Unfortunately, some carriers refuse to honor caller ID based on certain criteria. Some examples of this behavior are:
- Japanese numbers beginning with +81 3XXXXXXX
- Australian 1300/1800 Numbers to Virgin/Optus
- Bulgarian number calling to Bulgarian Mobiltel number
Also, making outbound calls from toll-free numbers is not supported. For more information, see the article: Can I make outbound calls with my toll-free number?