I’m going to attempt to answer my own question… If there is anyone on here that understands where I’m going with this, any feedback would be appreciated.
In short, I was attempting to create a printed page that showed a variety of QR Codes that represented various donation amounts. These always worked ‘for a while’. Then, the QR codes fail with the message ‘‘something’s not right. This page does not exist’, after a period of time.
As I mentioned in my original post, the QR codes worked for some hours (I didn’t measure it exactly) and then the error message appeared.
So, on doing some investigation, I discovered:-
The PayPal URL to the various donations includes an ‘access token'(whatever they are!) as part of the url. Therefore the QR Code I created at the time was fine. However, the access token apparently has a finite life (I read 9 hours???). After that, if the access token becomes invalid – and therefore the URL doesn’t work – and another is generated (but of course, the QR code doesn’t know that – and fails, because the URL does not exist any longer).
I’ve concluded, therefore, it’s not possible to create a QR code that I can print that takes a user to the ‘donate’ page for different amounts. If this conclusion is incorrect, I’d love to know how to get this sorted. Thanks, Steve