A quick guide on how to solve the “Your purchase not been completed. The Payment processor has reported an authorization failure. Please select a different payment method.” Steam PayPal bug.

First off, a caveat: Now, I'M NOT SAYING THIS WILL WORK FOR EVERYONE but I’m just sharing this because it worked for me. To phrase it another way, I’m not claiming this will work for all of you guys. I’m just trying to help those I can.