You have attempted to send to a mobile subscriber who has opted out to receive an SMS from you.
Mobile subscriber has:
Replied STOP to your previous message or
has a Premium Messaging block on their mobile account
- Remove the mobile number from your address book
- Advise the mobile subscriber to opt in to your text alert again (if replied STOP)
- Advise the mobile subscriber to contact their wireless operator to remove the Premium Messaging block from their account and opt in to your text alert again