Common causes
- The recipient phone number is invalid or missing the country code
- The recipient does not have WhatsApp on that number
- The recipient has blocked your number
- Your number was rate-limited or temporarily restricted by WhatsApp
- The connection sending the message went offline mid-send
Steps to diagnose
1
Check the phone number format
It must include the country code (for example,
+1, +91, +55).2
Check the connection status
Open Connections. Make sure the sending number is connected.
3
Try sending again
Open the chat or campaign and retry the send.
4
Test with a known-good number
Send to a colleague to confirm the connection itself works.
5
If many recipients failed
Your number may be rate-limited. Slow down sends, enable randomize sender, or pause to let limits reset.
Tips
- If undelivered messages are a recurring problem on one number, that number may have a poor sender reputation. Add more connections and rotate.
- For campaigns, use randomize sender and randomize message together to protect deliverability.