At work today I was tasked with setting up a Login with PayPay type of app, where, instead of filling out a registration form, you just login with an existing account, you've probably seen this type of thing with Facebook and Twitter, well the PayPal one is just the same. However when it came to passing the user over to PayPal to login, i received the following error message: IDSW_333 - there may be missing request parameters or this site is not approved to use After checking all my parameters, I could find nothing wrong. A Quick Google search found people have had the same problem, but it was mostly to do with using OpenId 1.0/2.0 and having to use OAuth 2.0 / Open ID Connect instead. This was never a problem for me since I was already using OAuth 2.0. The Solution In order to fix the annoying error message I simply deleted my existing app and created a new one, making sure I updated my App ID and App Secret in my program. This worked first time and allowed...