Paypal Express checkout only works for base site/currency in multi-site setup

Question

I have a site with multiple store fronts where every front has its own top level domain, language and currency. I have activated the built-in paypal express in my Magento 1.7.0.2.

Paypal now works fine as an option for my swedish front. Note that my store's base currency is in swedish currency (SEK). Paypal does not work in any other front such as the UK front which uses british pounds.

For the non-swedish fronts the checkout sends the user to a completely blank page on that front's domain such as https://ourdomain.co.uk/paypal/express/start/

Anybody with clues on what the issue could be? Is PayPal express at all meant to work on a multi-site environment? Could the problem be the currency, the different domains or something else? All ideas welcome.

Answer 1

Solved it!

Uncommented “ini_set('display_errors', 1);” from my index.php page which enabled me to see an error message instead of the blank page. Turns out the problem was a conflict with our unirgy gift certificate module. After disabling that module everything works.