So I've already seen a couple of the other answers to this question on almighty Google, however, my problem is still persisting.
Whenever someone tries to purchase an item using PayPal Express, when they click "Pay Now" it sends them to the Magento Review Page and throws the error "Please specify shipping method". However, if the user goes back to the PayPal Express page, and tries to pay again, it will go through just fine.
Whilst digging through the Magento files to try and see the issue, I've tried the following things.
Set the Timeout Callback on the shipping options to 6s
Added
/**
* Start Customization
*/
if (!$rate) {
Mage::logException(new Exception("Rate was empty inside quote validate method, trying to forcefully recalculate"));
$this->getQuote()->getShippingAddress()->setCollectShippingRates(true);
$this->getQuote()->setTotalsCollectedFlag(false);
$this->getQuote()->collectTotals();
$rate = $address->getShippingRateByCode($method);
}
/** End Customization **/From This Question
And I've tried logging the entire process.
What I've gathered from everything is that it looks as though Magento isn't picking up the Shipping Method returned by PayPal, as the Method and Rate from the function _validate() (in/app/code/community/sale/service/quote.php) are Both empty when the pay now action is processed.
Paypal is definitely returning the shipping methods too.
If you need any extra code etc, just comment below.
Any help would be greatly appreciated. 
Thanks!
