If you have seen this error, it means that the account you are currently logged into with Sauce is different from the account you are currently logged into on Instagram with. What to do in this situation depends on what you are trying to achieve:
If you are trying to use Sauce with a different Instagram account, then please see the following article: How to use Sauce with a different Instagram account.
If on the other hand, you are trying to use re-authorize the current account you are already logged into Sauce with, then you'll need to:
Head over to Instagram, and log out
Log back into Instagram with the account matching your Sauce username
Head back to Sauce and visit the 'Instagram Feed' tab which will re-authorize you
A final possible scenario is that you have changed your username on Instagram and want this reflected in your Sauce username. This is a process that will happen automatically, usually in less than a day. If this does not happen for you, then please reach out to us.