These are Instagram and Meta platform rules, so they apply to every tool, including ManyChat. There are no tool-specific settings to change here, this is simply how Meta's messaging windows work.
Almost every "my automation won't send" problem comes back to one thing: Instagram has two different messaging windows, and most people mix them up. Get these straight and a huge amount of confusing behavior suddenly makes sense.
The 7-day window: your first reply to a comment
When someone comments on your post or reel, you can send them one private-reply DM, and you have 7 days from the comment to do it. This is the window comment-to-DM automations run on. It's far more generous than people assume, which is good news: if a post goes viral and your tool can't DM everyone instantly, you still have a full week to catch the ones you missed (more on that below).
The 24-hour window: the ongoing conversation
Once a real conversation is going, a different rule applies. You can only send a free-form proactive message within 24 hours of the user's last message to you. Two things people constantly get wrong here:
- It resets on THEIR message, not yours. If your last message was to them and they haven't replied, the window is closed until they write back. Sending yourself doesn't extend it.
- Follow-ups in a comment flow fall under the 24-hour rule. Your first comment-triggered DM uses the 7-day private-reply window, but any later message in the same flow is measured from the user's last interaction under the standard 24-hour window.
7 days to send the first DM after a comment. 24 hours from the user's last message to send anything else. The 24-hour clock only resets when they message you.
Why you can't reactivate your old contacts
This is the most common window question. You build a sequence, target contacts who last interacted 60+ days ago, set it live, and nothing sends. Your setup is fine, the window is blocking it. Those contacts are far outside the 24-hour window, so your tool silently blocks the sends to avoid breaking Meta's rules. The sequence is live, but nothing goes out. That's policy enforcement, not a broken trigger.
Bulk re-engaging cold IG or Facebook contacts isn't doable within Meta's rules on any tool, so don't switch platforms expecting it to work elsewhere. Your realistic options:
- Wait for them to reopen the window by messaging you again.
- Move re-engagement to a channel built for opt-in outreach: email, or WhatsApp with approved template messages, which can message outside the window but still requires their prior opt-in.
The only Meta-sanctioned way to reach IG/FB users outside the window is an opt-in recurring-notification list they explicitly subscribed to beforehand, and Meta has been winding those options down. People who just DM'd you once never opted in, so that path isn't open for them.
While we're here: the rate limit
For comment-triggered DMs, Meta documents a ceiling of 750 private replies per hour per account. A few hundred a day spread out is well within that. What actually gets accounts flagged is a sudden burst from a new or dormant account, not the daily total, so ramp new accounts up over a couple of weeks and vary your message text.
The 7-day window is also a recovery tool
Because you have 7 days to send the first comment reply, missed commenters from a viral post aren't gone, they're recoverable. ChatGenius has a feature called Rewind that re-scans a post and sends the DM to everyone who matched your keyword but never got one, as long as they're still inside that 7-day window. It's the difference between losing the overflow from a spike and catching it.
See how Rewind works Or start free.Frequently asked questions
Both, for different things. The first DM after a comment uses the 7-day private-reply window. Follow-ups and proactive messages use the 24-hour conversation window measured from the user's last message.
When the customer messages you, not when you message them. If your last message was outbound and they haven't replied, the window is closed until they write back.
They're outside the 24-hour window. Contacts inactive for weeks or months are way past it, so your tool silently blocks the sends to stay within Meta's rules. The sequence runs but nothing goes out.
Only if they message you again, or via an opt-in list they subscribed to beforehand. For real outside-window outreach, use email or WhatsApp template messages (which still need opt-in).
Meta documents 750 private replies per hour per account for comment-triggered DMs. A few hundred a day is fine. Sudden bursts from new or dormant accounts are the real flag risk, not the daily total.