"Error trying to decode a non urlencoded string"

A patron reports that she is unable to access locked content. ETA: https://whatsmybrowser.org/b/XGK3HM5

Cleared cache, logged into Patreon, went to site, clicked “Unlock with Patreon” button, received an email that said “click here to open” but when she clicked it she got this:

Does she still get this error? And also does she get this error from any other device/browser?

Yes she has been getting this error for a long time. She cancelled her Patreon account because of it - why pay if she doesn’t get the promised rewards?

Do you have any other patrons experiencing this issue?

I don’t think so, no one else has ever reported this particular error.

I very much suspected so. The thing is that this has not been reported by anyone else either. That makes this case pretty difficult.

From what it seems she clicked something in her email? This should not have happened or needed to happen after she clicked unlock button at your site - she is supposed to be immediately sent to Patreon, where she could give permission to your site, and then be sent back.

Her email client could have modified the link text and made the url encoding to fail.