I see there was a bug report entered around 2 months ago regarding this same issue. I noticed it was marked "Resolved". If the resolution was to disable your Paypal security key in order to make a purchase, that does not meet the definition of resolution. :) Detailed Description of the Problem With a security key attached to your Paypal account, when you attempt to login via the Paypal window from, for example, the Marketplace, it reports it as an invalid username or password. The error is incorrect and the purchase cannot complete. Steps to Reproduce the Problem Follow the steps above. Enable any kind of security key (two factor authentication) and attempt a Paypal purchase on Roll20. Description of Your Setup (Browser + Version, Operating System, etc.) (A good place to get that info if you don't know it: <a href="http://supportdetails.com/" rel="nofollow">http://supportdetails.com/</a> ) As this appears to be an issue with Roll20's implementation of Paypal, these things don't seem relevant, though I can provide them if needed. I assume that Roll20 is hard at work on something that could be denying them or content creators in the marketplace a source of revenue!