As of this afternoon I’m getting a 403 HTTP error after submitting credentials on the OAuth sign-in page. I haven’t changed anything in my code which has been working fine until now.
The 403 happens during the procedure described here: https://dev.twitter.com/docs/auth/implementing-sign-twitter. As part of step 2 I show a webview which loads https://api.twitter.com/oauth/authenticate?oauth_token=<request token obtained in step 1> (the sign-in page). Then after submitting my account credentials on that page, I get this error: “403 Forbidden: The server understood the request, but is refusing to fulfill it.” This happens both when I enter wrong credentials and when I enter the correct credentials.
I really have no idea what’s going on here since I didn’t change anything. The error doesn’t show up in other apps. I also tried using different IP addresses, but no luck there either.