Quote Originally Posted by DML73 View Post
Thanks a lot. I did as specified on that page however Im still getting the errors ReturnURL is invalid and CancelURL is invalid messages when I look in /includes/modules/payment/paypal/logs.

I have also entered the the correct return URL in PayPal to one of my sites https://www.my-site.com/index.php?ma...eckout_success
This URL works fine for both my sites when I enter them manually in a browser.

Any idea what the problem could be?
If your PP payment module is correctly configured in the admin then the return url is automatically generated by Zc and the customer is returned to the correct store.

Are you using PP Standard or PP Express Checkout?

Suggest you have another look at the link stevesh has posted for you and also check that your PP module is configured as per tutorials and post on this site.