Instagram comment automation only sending DM to some users

Instagram comment automation only sending DM to some users, not all. I have a comment growth tool set up so when someone comments on my post they get a DM with a waitlist link. Some commenters receive it fine but others never get anything. Already reconnected the Instagram page to ManyChat and that didn't fix it. Could this be Meta's 24 hour messaging window, keyword matching issues, or a rate limit on DMs. Has anyone run into this and found a fix. Is there a way to see why a specific comment failed to trigger the automation.