I have been working with Login And Pay With Amazon Automatic Integration Guide. Amazon has provided a document for the same: http://docs.developer.amazonservices.com/en_US/pay_with_amazon_automatic_payments/APAGuide_GettingStarted.html
But the problem is - document is for US marketplace and I am implementing for UK. Now when I implement the same, it returns the error:
"Unknown client ID".
Can anyone please help me in the same. I have been working on this from past 3 days, and it comes out like a mess to me.
You should be following the UK guide. http://docs.developer.amazonservices.com/en_UK/apa_guide/APAGuide_GettingStarted.html