This error appeared from nowhere and yes, I have seen the manual talk about when using test transactions. I've changed to PayPal Standard and the error doesn't come back because the PayPal Express button is no longer there. The error also appears when clicking the "Bill Me Later" button - so I have disabled that in the config. Was looking at the source code and this error only appears in the PayPalController file as an exception to a Try/Catch segment.
Yes, I have checked all the settings and they are correct.
Been able to use PayPal Express in the past with no problem - have made zero modifications. Don't know if this is on my end or on the PayPal end of things.
Any help would be appreciated.- Thanks, William