We have found evidence that there are still problems for some customers connecting their Instagram Business accounts in quintly, even with granting us the additional business_management permission. This fits with some reports on the bug report: https://developers.facebook.com/support/bugs/217599355760582/?disable_redirect=0
We are still waiting for a response from Facebook.
WARNING: There is a proposal for a workaround floating around, converting the Instagram account back to a private profile and then back to a business account again. WE DISCOURAGE from doing this, or otherwise you will lose access to your Instagram Insights history, not only in quintly but highly likely also directly in your Instagram account. The Insights history gets build up from the day of the last business account transformation onwards.