Instagram login API is in use. After approving the app, the following error occurs.
The user denied your request.
It worked well until yesterday. What's the problem?
The value of the authorization buttons is different in other languages which probably causes the issue, I guess an issue on Instagram itself.
After doing some research I found out you can change the language of the authorization screen using the following parameter:
&hl=en
Did some test with my apps and it's solving the issue.
Note: The language parameter is not in the official documentation, so in theory they could change it, but for now it is fixing the issue.