⚡ Quick answer -

Undelivered WhatsApp messages are most often caused by:

• Reaching Facebook’s daily marketing-template limit for a user

• Recipient blocks, opt-outs, invalid or inactive numbers

• Unapproved, paused, or rejected templates

• Billing problems with the WhatsApp Business API account or rare service outages

• Sending non-template messages outside the 24-hour customer-service window

When should I use this guide?

Consult these checks whenever a WhatsApp Business API message is stuck in “pending” or “failed” status. The sections below keep the original facts intact and walk you through limits, templates, recipient issues, and provider error codes.

1. Overview of key causes

WhatsApp messages may not be delivered for several reasons related to message limits, recipient status, template approval, account issues, or service outages.

2. Detailed root-cause categories

2.1 Marketing message limits

• Facebook imposes a daily limit on marketing template messages sent to a user.

• Once this limit is reached, the user will no longer receive additional marketing messages.

• The error message may indicate that “to maintain a healthy ecosystem, the message was not delivered.”

2.2 Recipient issues

• The recipient may have blocked the sender.

• The recipient may have opted out of receiving messages.

• The recipient's phone number may be invalid or inactive.

2.3 Template problems

• The message template used may not be approved by Meta.

• The template could be paused or rejected.

2.4 Account or service issues

• There could be billing problems with the WhatsApp Business API account.

• Rare WhatsApp service outages can also cause message delivery failures.

2.5 24-hour customer-service window

• WhatsApp allows free-form messages only within a rolling 24-hour window after the customer’s last message.

• Outside this window, only pre-approved template messages can be sent.

• Sending non-template messages outside the window results in delivery failure or “template required” errors.

3. Troubleshooting steps

• Test sending a utility template message (e.g., order confirmation) to the problematic number. If it delivers, the issue is likely with marketing message limits or the marketing template.

• Test sending the original message to a different valid WhatsApp number you control. If it delivers, the problem is with the original recipient's number (blocked, invalid, offline). If it still fails, the issue is with your message template or API account.

• Check your WhatsApp Business API provider's dashboard or logs for specific error codes or messages related to the failed delivery.

• Ensure you are using approved templates when sending messages outside the 24-hour window.

• Contact your API provider's support team with relevant details if the problem persists.

4. When will messages be delivered?

Messages will deliver successfully when:

• Marketing-template limits have not been reached.

• The recipient has not blocked or opted out, and the number is valid and active.

• The template is approved, active, and used correctly.

• The WhatsApp Business API account is in good standing, and no outage exists.

• Messages sent outside the 24-hour window use a pre-approved template.

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