"Can't send messages to this recipient because they blocked you" Salesforce Messaging

Codes starting with two (2xxx) indicate a problem with the destination address.
2002 - Can't send messages to this recipient because they blocked you.
 
 
This exception is thrown since the recipient blocked the channel. Check the "Messaging Consent Status" of the Messaging End User to resolve this issue.
 
The "Messaging Consent Status" of the Messaging End User shouldn't be "Opted Out".