40300 – Blocked due to STOP message
Messages cannot be sent from your number to a destination number because the destination has sent your number a stop message. Stop messages are those that consist solely of one of the following words (case and whitespace insensitive):
- CANCEL
- END
- QUIT
- STOP
- STOPALL
- STOP ALL
- UNSUBSCRIBE
40300 – HTTP Status – 409
Messages cannot be sent from {src} to {dst} due to an existing block rule.
40300 – Causes
- The recipient has sent a stop message from their number to yours.
40300 – Solutions
- Instruct the recipient to send a message containing only the word "START" from their number to your blocked number.