Hi there,
Muhammad is correct! In Instantly, if you don’t uncheck the “Skip leads if in another campaign” option, it won’t add the lead to the campaign.
Another possibility is that the lead is already in the campaign and was just updated instead. Unfortunately, Instantly doesn’t provide clear reporting for this action, so it shows “Failed to add” when it should say “Updated.”
Let me know if you need help troubleshooting further! 😊