When authenticating your Instagram account directly through Instagram instead of Facebook, you must enable the "Connect future activity" permission in your Instagram settings.
If you do not have this permission enabled, you will see this error message when attempting to authenticate:
This error occurs because Instagram requires the Off-Facebook Activity setting (also called Future Activity) to be enabled. This occurs because Instagram reviews your Off-Facebook Activity settings as part of Meta’s built-in security measures.
To fix this, you’ll need to turn on Future Activity in your Instagram Account Center settings.
How to Turn On Future Activity
Log in to Instagram at Instagram.com.
In the bottom-left corner, click More to open additional options.
Click Settings.
Select See more in Accounts Center.
In Accounts Center, go to Your information and permissions > Your activity off Meta technologies.
When the settings modal opens, click Manage future activity.
Toggle on Connect future activity and click Confirm to save your changes.
Return to Measure Studio and try adding or reconnecting your Instagram account again.