25022: Duplicate username or externalId

Twilio returned this error because the username or externalId you provided already belongs to an existing user. Each user must have a unique username and, when provided, a unique externalId.

• You attempted to create a new user with a username that is already assigned to another user.
• You attempted to create a new user with an externalId that is already assigned to another user.
• Your application retried a user creation request and sent the same identity values more than once.
• Your integration does not check for existing users before creating a new one.

• Update the request so the username is unique for the user you want to create.
• Update the request so the externalId is unique if your integration uses that field.
• Check whether the user already exists before sending a create request.
• If you intended to modify an existing user, update that user instead of creating a new one.
• Review your application's retry and provisioning logic to prevent duplicate user creation requests.

• Identity and Access Management docs
• Manage users with Twilio Identity and Access Management