Instagram returning “Matching code was not found or was already used” when using OAuth

Question

I am trying to use the Instagram OAuth using the developer documentation at

https://www.instagram.com/developer/authentication/.

Step 1 and 2 a

Answer 1

We are also experiencing the same issue from yesterday, looks like clearing browser (or new incognito window) do the trick. Although, the mobile app where we are authenticating through mobile browser, working fine.