Instagram access to incoming messages
You must have one inbox for both the business page and Instagram business account.
To do this, you need to go to your business page and select the “Meta Business Suite” tab
Click "Inbox"
Confirm your business account (if this popup is not shown, you do not need to confirm).
You need to confirm access to Instagram messages from the business page. You will not see messages from users in Smart Sender until you do it.
After clicking on “Confirm connection“ you will be redirected to the Instagram login page, if this does not happen, make sure that your browser has not blocked the pop-up window.
After a successful login, you will be redirected back to the Inbox page. If it doesn't happen within 30 seconds, refresh the page. Go to the "Instagram Direct" tab and you will see a page like this.
Now you can connect your Instagram account to the Smart Sender platform. See this instruction: Instagram connection