Instagram's 24-hour messaging window, explained

Short answer: when a customer messages your Instagram professional account, a business tool has 24 hours to reply through Meta's API. After that, Meta rejects the reply with error code 10, "This message is sent outside of allowed window." The window only reopens when the customer messages you again. A person on your team (not a bot) can reply for up to 7 days using Meta's Human Agent tag, but only if the app sending the messages has Meta's Human Agent permission.

This is Meta's policy, not a bug in your inbox, and no setting turns it off. The same rule applies to Facebook Messenger.

What the error looks like

Code	Meta's message	What it means
10, subcode 2534022	"This message is sent outside of allowed window."	The customer's last message is more than 24 hours old
10, subcode 2018278	"This message is sent outside of allowed window."	The type of message isn't allowed in this situation
551	"This person isn't receiving messages from you right now."	The person can't be reached, for example they've blocked you. Waiting won't help.

Code 10 means wait for the customer to write. Code 551 means the conversation is closed on their side.

What opens and reopens the window

The window opens when the person sends your Instagram account a message, and each new message from them restarts the 24 hours. Replies to your stories arrive as messages, so they count too.

Your own messages never extend the window, however many you send.

Why a business can't message first

Through the API, a business can't start an Instagram DM conversation. The customer has to write first. This catches out teams coming from WhatsApp, where businesses can start conversations with paid, pre-approved templates. Instagram has no equivalent, and Meta's policy says One-time Notifications, Sponsored Messages and News Messaging are not available for Instagram.

So a contact you imported, or someone who only liked or commented on a post, can't be sent a DM until they message you.

The one exception is comments. Meta lets a business send a single private reply to someone who commented on your post or reel, within 7 days of the comment, and follow up only if they answer. Omni doesn't send comment private replies at the moment. Use the Instagram app for those.

The Human Agent tag (up to 7 days)

Meta's Human Agent tag lets a person on your team reply up to 7 days after the customer's last message. It's meant for cases like a weekend closure, or an issue that takes more than a day to resolve.

• Only for replies written by a person. Using it for bots or automated messages breaks Meta's policy.
• It needs Meta's approval. The app sending the messages must be granted the Human Agent permission through Meta's App Review.

Omni supports the Human Agent tag. When it's enabled on the platform, a reply you send between 24 hours and 7 days after the customer's last message is automatically sent with the tag. Until then, the 24-hour limit applies.

How Omni prevents failed replies

We learned how confusing this rule is from our own inbox. Early on, a teammate reported "it says the window is closed, but they messaged today". The chat showed times without dates, and the customer's last message was actually a week old. The system was right; the interface made it look wrong.

So Omni now:

• records when the customer last wrote in every Instagram and Messenger conversation,
• checks the window before sending, and explains why a reply can't go out (including the date of the customer's last message) instead of creating a failed message,
• shows day separators in the chat and dates in the conversation list,
• shows a banner and locks the reply box while the window is closed.

Common mistakes

• Treating error 10 as a bug or a permissions problem. Check the date of the customer's last message first.
• Planning an Instagram DM campaign to imported contacts. It isn't possible. Use WhatsApp templates, ads or organic posts for outreach.
• Using the Human Agent tag for automations. It's for human replies only.
• Assuming Messenger rules carry over. Messenger has some message tags that Instagram doesn't.

FAQ

What is the Instagram 24-hour messaging window?

The period after a customer messages your Instagram professional account during which a business tool can reply through Meta's API. It lasts 24 hours from the customer's most recent message.

Can a business send the first Instagram DM through the API?

No. The customer has to start the conversation. The only exception is one private reply to a comment on your post, within 7 days of the comment.

Does sending more messages keep the window open?

No. Only messages from the customer open or reset it.

Is the rule the same on Facebook Messenger?

Yes, the 24-hour standard window is the same. See Connect Messenger and Instagram.

Related: Team inbox · Messenger and Instagram