Question:
I tried to use Chat Broadcast but it only sent 4 messages and the rest has this error, (#10) This message is sent outside of allowed window. Learn more about the new policy here: https://developers.facebook.com/docs/messenger-platform/policy-overview”
Answer:
This is not an error but a Messenger Policy that if you don't use message tags, your broadcast will only be sent to your subscribers who interacted with your page in the past 24 hours. If you want to send your broadcast to all your subscribers, then you must use a message tag.
You may learn more about Messenger Policy through this link:
https://developers.facebook.com/docs/messenger-platform/policy/policy-overview/
Please note that automated tagging for multiple users is not supported. However, if this is for Chat Broadcasting, you can use Match Type filter. Please refer to the image below:
