If you are a business that uses WhatsApp Business API to scale your business then you might have faced problems in delivering message to users with the 131026 error that shows the following error message:

"errors": [ { "code": 131026, "title": "Message Undeliverable." }

Possible Causes for the #131026 Error [Officially Listed by Meta]​

There are several reasons this error might occur as officially listed by Meta:

  • The recipient’s phone number is not linked to WhatsApp.

  • You are trying to send an authentication template to WhatsApp users in India, which is currently not supported.

  • The recipient has not accepted Meta’s latest Terms of Service and Privacy Policy.

  • The recipient is using an outdated version of WhatsApp.

Possible Causes With Solutions for the #13026 Error [Suspected by Heltar]

To help you troubleshoot the error effectively, here are possible solutions suggested by Heltar:

1. Send a Utility Message (To check for marketing frequency cap)

To narrow down the cause, try sending a utility message (non-marketing) to the phone number that triggered the error. If the utility message is delivered successfully, it likely means the original marketing message was blocked by WhatsApp to maintain what Meta calls a ‘healthy ecosystem’.

What is meant by WhatsApp Healthy Ecosystem?

WhatsApp has implemented Marketing Template Frequency Capping to maintain a healthy environment for users and protect them from being overwhelmed by excessive marketing messages. This system limits the number of marketing messages from businesses a user receives within a certain timeframe, although the exact limits are dynamic and undisclosed by Meta.

Here's how Frequency Capping works:

If a user receives too many marketing messages in a short period or fails to engage with previous messages, WhatsApp may block further marketing messages to protect them from spam. For example, if six brands have sent marketing messages to a user, WhatsApp may block a seventh, even if that brand is reaching out to this user for the first time.

Since the marketing frequency applies only to marketing messages you can send a utility message to the customer if it’s urgent. 

If you absolutely need to send a marketing template message you can try the below steps:

  • As the cap is not permanent, try sending marketing messages at increasing intervals (e.g., after two days, then a week, and so on).

  • Check if users have read (message has blue ticks) the previous marketing messages (in WhatsApp API it comes as a webhook). If a message has gone unread, use an alternate communication channel to prompt users to open it. This helps prevent further undelivered messages.

Although WhatsApp has now shifted the message undeliverable error due to frequency capping to error code 131049 with the message: "This message was not delivered to maintain healthy ecosystem engagement", we suspect that in some instances, it may still trigger the 131026 error under similar circumstances.

Read more about Meta’s Marketing Message Frequency Capping for Healthy Ecosystem on WhatsApp.

2. Send a plain-text utility message (To check if customer’s WhatsApp version is outdated)

If the marketing message is not delivered, try sending a basic plain-text utility message with no formatting, links, or buttons. If this message goes through, it indicates that the user’s WhatsApp version is outdated and cannot render advanced message formats (such as those with buttons, links or carousels). In this case, either send a simple text-only message or encourage the user to update their WhatsApp to the latest version.

3. Other Reasons

If the plain message is also not delivered then this means either the recipient's phone number is not on WhatsApp or they haven't accepted WhatsApp's latest terms and conditions and you will have to contact them through an alternate communication channel. 

For more insights on WhatsApp Business API, check out more blogs at heltar.com/blogs.