So I have a web app that login to Instagram. Works fine for months. No code changes, and suddenly I'm getting
{"code": 400, "error_type": "OAuthException", "error_message": "Matching code was not found or was already used."}
Logging out of instagram.com on my browser and using my web app to login with instagram oauth.... now it works. And it works repeatedly (logging in and out of my app with instagram oauth). Works fine.
Until I access a www.instagram.com webpage on my browser. Then my oauth login fails again with the same error. And I can't login to my web app with instagram oauth again until I logout of instagram.com itself
Same problem happening here: Instagram returning "Matching code was not found or was already used" when using OAuth
Seems like it's on Instagram's end.