This is one of the most common questions about comment to DM automation: "It worked for ten people, then three people said they got nothing." The automation is not broken. Something about those particular comments, or those particular people, is different. Here are the usual reasons, in the order worth checking.
1. The comment did not match your keyword
If your keyword is price and someone writes "rate?" or "how much", the automation will not fire. Open your activity log and look at the exact text of the comments that got nothing. Add the missing words as extra keywords. DM Flow allows up to 20 per automation and ignores capital letters.
2. It was a reply to another comment
Some people reply under someone else's comment instead of writing a new one. Depending on the tool and how Instagram delivers that reply, it may not be treated as a fresh comment on your post. Ask people to "comment" rather than "reply" in your reel.
3. The same person commented twice
Instagram allows one private reply per comment, so each comment can only ever get one automated DM. Some tools also skip people who already got the DM on that post. If someone says "I commented twice", check whether either comment matched your keyword.
4. They commented from your own account
Instagram does not let an account message itself. If you test by commenting from your business account, nothing will arrive. Always test from a second account.
5. Their message settings or account limits
The DM can be delivered but land in message requests, especially when the person does not follow you. They might simply not have seen it. Remind people in your reel to check their message requests.
6. You hit a sending limit
Instagram limits how many automated messages an account can send in an hour, and plans have monthly DM limits. During a viral spike some comments can be paused. Your activity log should say "limit" or "paused" against those comments. Read Instagram DM limits per hour.
7. The comment arrived late from Instagram
Very rarely Instagram delivers a comment event late, or a comment is held by its own spam filter. If a comment never appears in the log at all, the tool never received it.
A quick checklist
- Open the activity log for that post.
- Find the person's username.
- Read the note next to their comment: no match, own comment, duplicate, limit or sent.
- Fix the cause: add a keyword, wait for the limit to reset, or ask them to check requests.
In DM Flow every comment is logged with a plain-language note, so you can see exactly why someone did or did not get a DM.
Related reading
Frequently asked questions
Why did only half my commenters get the DM?
Usually the other half wrote words that do not match your keyword, replied under another comment, or commented twice. Check the activity log for each username.
Can I resend the DM to someone who missed it?
You can reply to them yourself in DMs within seven days of their comment. Automations answer each comment once.
Does the DM fail if the person does not follow me?
No. It is still sent, but it may appear in their message requests instead of the main inbox.