Work through this list:

1. History > Sending – are the messages there with an Error Count? Open one to read the error.
2. Balance – the sending job stops with "NO CREDITS" when the balance is not above the per-message rate. Top up or enable Auto Recharge.
3. A2P registration (US/CA) – the job refuses to run until the campaign is verified and a number is attached ("You need to comply with US A2P 10DLC Regulations").
4. Number status – the From number must be Active.
5. Background jobs – the sending job processes up to 50 messages per run; very large campaigns take several runs, and if your site's scheduled jobs are not running, nothing moves (contact Sprwt support).
6. Recipients – if the confirmation showed 0 recipients, no messages were created.