Failed to send message because this user's phone number is part of an experiment

When sending a Template, the message is not sent and an exclamation mark appears.

Error: Failed to send message because this user's phone number is part of an experiment

The cause of the Error can be checked at the link below:

Experimentsdevelopers.facebook.com

Translating Meta's explanation:

Occasionally, we run experiments to help us assess the impact of messages on user experience and engagement on WhatsApp. These are standard practices on our platform and help us improve the messaging experience for you and your customers.

Ongoing experiments are described below and do not have a fixed end date. To protect the validity of the experiment and ensure the best possible business and consumer experience, we cannot provide any exceptions or opt-outs for these experiments.

Marketing message experiment

Starting June 14, 2023, about 1% of WhatsApp users will not receive marketing template messages from any business unless one of the following conditions is met:

• there is a customer service window between the customer and the business

• there is an open marketing conversation between the customer and the business

• there is an open and free inbound conversation between the customer and the business

If you send a marketing template message to a customer who is part of the experiment group, your message will not be sent and you will not be charged for it, since no conversation was created. Instead, you will receive an undelivered webhook status message containing error code 130472, notifying you about the failure.

Attempting to resend the message will result in the same error. If you need to deliver the marketing template message to the customer, we recommend that you contact the customer by some other means than WhatsApp and ask them to send you a message so that you can resend the message within the customer service window.