Troubleshooting - Vodafone Bulk Text Developer Portal

Use this page to diagnose common authentication, campaign, Sender ID, and callback issues.

Authentication issues

Symptom	Likely cause	Fix
`401 Unauthorized` from the API	Missing, expired, or invalid access token	Request a new token and retry the API call.
`invalid_grant` from the token endpoint	Incorrect username or password	Check the credentials supplied for the Bulk Text account.
Token expires during processing	Access tokens are short-lived	Re-authenticate before requests or retry once after `401`.
Request is rejected by the token endpoint	Wrong content type or form body	Send `application/x-www-form-urlencoded` with `grant_type=password` and `client_id=ismstoken`.

See Authentication for complete examples.

Campaign request issues

Symptom	Likely cause	Fix
`415 Unsupported Media Type`	Request is not JSON	Send campaign requests with `Content-Type: application/json`.
Message is not accepted	Missing required field	Include `text`, `from`, and at least one `recipientInfo` entry.
Some recipients are skipped	Invalid recipient numbers	Review the `errors` array and correct the affected `msisdn` values.
Account has no credits	Message processing returns a credit error	Add credit or contact bulktext.ie@vodafone.com.
Scheduled message does not send when expected	`sendAt` is not UTC or has the wrong format	Use UTC in `yyyy-MM-ddTHH:mmZ` format.

Sender ID issues

Symptom	Likely cause	Fix
Sender is not valid	`from` is not approved on the account	Call `GET /api/v2/senderlist` and use one of the returned values.
Irish recipients do not receive messages	International non-ComReg Sender ID used for Irish traffic	Use a Type `0` ComReg Sender ID or Type `2` numeric Sender ID.
New Sender ID is unavailable	Registration is not complete	Contact bulktext.ie@vodafone.com.

Callback issues

Symptom	Likely cause	Fix
No webhook arrives	Callback URL is not configured	Send your HTTPS endpoint to bulktext.ie@vodafone.com.
Vodafone cannot deliver callbacks	Endpoint does not accept POST or TLS requirements are not met	Ensure your endpoint accepts `POST`, supports TLS 1.2 where required, and returns `200 OK`.
Duplicate callback processing	Handler is not idempotent	Store callback IDs or use `notifyId` plus timestamp/status to deduplicate.
DLR arrives late	Mobile network delivery status is delayed	Accept late DLRs and keep messages in an unconfirmed state until your timeout expires.
Verification hash does not match	Wrong verification key or hash input	Check the documented formula and confirm the verification key for your account.

Legacy API issues

The v1 URL-encoded API returns plain-text status codes and messages, sometimes inside a 200 OK HTTP response. Always inspect the response body before treating the request as successful. See Legacy API overview and the URL-encoded legacy endpoint in the Legacy APIs sidebar.

Last modified on May 6, 2026