The 24-hour messaging window is the period in which you can send any text you like to a person. It opens the moment they write to you and closes 24 hours after their last message; once it closes, the panel says a reply cannot be sent. This is Meta's rule and it applies to every tool built on their API — it is not a restriction the panel invented.
In this article you will find:
What the window is and why it exists
What opens the window and what does not
What you can do while the window is closed
Where to see the window in the panel
Three situations, with examples
Common mistakes
What the window is and why it exists
Meta does not want businesses messaging people whenever they feel like it. The rule they settled on is simple: the person starts the conversation. When they write to you a clock starts, and until it runs out you can send text, photos, video, files, messages with buttons — whatever you need. When the clock runs out, free-form sending stops.
The period is 24 hours on both Instagram and WhatsApp.
The window is per person, not per account. On the same account one customer's window can be open while another's is closed.
What opens the window and what does not
Only a message the person sends you opens the window. Every incoming message restarts the clock.
Contacts that do open it:
Text, photos, video, voice notes and documents the person sends.
A reply to your story, and being mentioned in their story — both arrive as messages.
Tapping a button or a menu option in a message.
Contacts that do not open it:
Commenting on your post or Reel. A comment is not a message.
Clicking your ad, or opening a chat from a link (ig.me, QR). The chat window appears, but the person has not written anything yet.
Following you, liking a post, watching a story.
⚠️ This is the most common surprise: "but they commented, why can I not reply?" In Meta's eyes a comment is not a message and does not open the messaging window. The way to reach these people is an automation that sends a private reply to the comment.
If the person has never written to you, the panel does not say "24 hours have passed"; it says This person has never sent you a message. Those are two different states: in one the clock ran out, in the other it never started.
Why the window does not renew when you send
The clock runs from the person's last message. No matter how much you write, the period does not grow.
That is deliberate. Otherwise a business could keep the window open forever by writing to itself after a single first message, and Meta's rule would mean nothing. The principle is: only the other side extends the time.
The same 24 hours apply to automations. If a flow tries to send while the window is closed, nothing goes out; the run log records it as "skipped" and the flow moves to the next step.
What you can do while the window is closed
There are three routes, and which ones you have depends on the channel.
An approved template on WhatsApp. When the window closes, a template picker replaces the message box in the inbox. You send a template Meta approved in advance, filling in its variables; the moment the person replies, the window reopens and you are back to free-form messages. See Sending a WhatsApp template.
Human agent on Instagram. Meta recognises a tag that extends the period to 7 days for a message written by a real team member. The extension is only used from the inbox, only when a human writes; automations cannot carry that tag. See Human agent and the 7-day rule.
A private reply to a comment (automation only). Sending a private DM from a comment ignores the window, but has rules of its own: once per comment, and within 7 days of the comment. This route belongs to automation flows, not to the message box in the inbox.
If none of these apply, the only thing to do is wait: the window reopens when the person writes again.
Where to see the window in the panel
The Messaging window badge sits in the Details section of the contact panel:
Green, "Open until …" — you can send free-form messages.
Green, "Human agent: until …" — the 24 hours are up but the human agent period is still running.
Yellow, "Window closed" — the period ran out.
Yellow, "No message yet" — the person never wrote to you.
Yellow, "Human agent window closed" — the 7 days ran out too.
When the window is closed you also see an explanatory line under the chat, and that line states exactly when the window closed rather than just saying it is over.
Three situations, with examples
A bakery receives an order message at 21:00. They reply at 09:00 the next morning: the window is open, no problem. When the customer writes "thank you" at 09:05, the clock resets and they are free until 09:05 the following day.
A shop looks at a Friday 18:00 question on Monday at 10:00. 64 hours have passed; the window closed on Saturday at 18:00. On WhatsApp they can reopen it with an approved "following up on your question" template. On Instagram, if the human agent period is available, a team member can still write directly, because they are inside the 7 days.
A café gets a "do you have a menu?" comment on its Reel. The person never sent a DM, so the window never opened. The panel says "No message yet" for this contact. What the café should build is an automation that sends a private reply to the comment; that first message starts the conversation, and if the person answers, the window opens.
Common mistakes
Thinking your own message extends the period. It does not. Only the person's message resets the clock.
Counting a comment as a message. A comment does not open the window. Neither does an ad click or arriving from a link.
Pressing "retry" over and over on a closed window. The reason is permanent; you will get the same answer however many times you press. The right route is a template.
Looking for templates on both channels. Approved templates belong to WhatsApp. Instagram has no templates.
Trying to send from an automation outside the window. Flow messages follow the 24-hour rule; the run log will show "skipped".
Related concepts
The full wording of the warning you see on a closed window, and the other send failures, are covered in Message could not be sent. For the whole contact panel where the window badge sits, see The inbox screen.
Knowing this one rule explains almost every "why can I not message this customer".