# 21727: Campaign registration failed due to missing parameter(s)

Log Type: APPLICATION

Log Level: ERROR

## Description

Twilio could not register your US A2P 10DLC campaign because the campaign creation request is missing one or more required parameters. Campaign registration requires core fields such as `brandRegistrationSid`, `description`, `messageFlow`, `messageSamples`, `usAppToPersonUsecase`, `hasEmbeddedLinks`, and `hasEmbeddedPhone`. Additional keyword and auto-reply fields may also be required depending on how your campaign handles opt-in, opt-out, and help flows.

### Possible causes

* The campaign creation request omitted one or more required core fields.
* The request did not include the required `messageSamples` values for the campaign.
* The campaign allows end users to opt in by texting a keyword, but the request did not include `optInKeywords` or `optInMessage`.
* The campaign manages opt-out or help responses outside Twilio's default or Advanced Opt-Out handling, but the request did not include `optOutKeywords`, `optOutMessage`, `helpKeywords`, or `helpMessage`.
* A required parameter was included in the request structure but was sent without a usable value.

### Possible solutions

* Review the campaign creation request and include all required core parameters: `brandRegistrationSid`, `description`, `messageFlow`, `messageSamples`, `usAppToPersonUsecase`, `hasEmbeddedLinks`, and `hasEmbeddedPhone`.
* Provide two to five representative `messageSamples` that match the campaign description and selected use case.
* If recipients can subscribe by texting a keyword, include both `optInKeywords` and `optInMessage`.
* If you manage opt-out and help behavior yourself, include `optOutKeywords`, `optOutMessage`, `helpKeywords`, and `helpMessage` in the request.
* If you use Twilio's default opt-out handling or Advanced Opt-Out on the Messaging Service, confirm that configuration before submitting the campaign and only omit custom help and opt-out fields when that setup applies.
* Recheck the request payload against the A2P 10DLC campaign requirements, then resubmit the campaign registration.

#### Additional resources

* [Gather the Required Business Information](/docs/messaging/compliance/a2p-10dlc/collect-business-info)
* [A2P 10DLC Campaign API Reference](/docs/messaging/api/usapptoperson-resource)
* [Troubleshooting A2P 10DLC Registrations](/docs/messaging/compliance/a2p-10dlc/troubleshooting-a2p-brands)