Outbound messages will go into a "Failed" state with Plivo error code 900 and are not forwarded to our downstream carriers. Post this, for the next 2 mins, all send message API requests will fail with the error "Insufficient Credit". This ensures that the customer can take necessary action before queuing any more messages in Plivo.

Note: All messages that are already queued in Plivo's system will continue to be marked "failed" with error code 900 as and when they are dequeued for processing until required credits are added to the account.