This problem suddenly appeared three days ago after I´ve used Paypal Express checkout for 1 1/2 years. The payment have been captured in Paypal, but in Magento backend there is no trace the payment has gone through. The order page shows the order as "processing" and I´m not able to generate an invoice. The payment is also not showing up in the total sales amount. Anyone encountered this before? Should I reinstall the payment solution?