Hi, just having a play with the latest dev version and I can't get past 'A problem was found connecting to PayPal. Please try again later'.

Looking at the log the issue is coming from the cart item amounts not matching the order amounts and this is happening due to VAT (UK and EU Tax)

PayPal EC API call DEBUG in SetExpressCheckout Array ( [ADDROVERRIDE] => 1 [REQCONFIRMSHIPPING] => 1 [NOSHIPPING] => 1 [PAYMENTREQUEST_0_ITEMAMT] => 245.00 [PAYMENTREQUEST_0_AMT] => 294.00 [PAYMENTREQUEST_0_INVNUM] => 6-1352198838 [RETURNURL] => http://xxx/checkout/6/payment/return/xxx [CANCELURL] => http://xxx/checkout/6/payment/back/xxx [PAYMENTREQUEST_0_NOTIFYURL] => http://xxx/commerce_paypal/ipn/paypal_ec%7Ccommerce_payment_paypal_ec [PAYMENTREQUEST_0_CURRENCYCODE] => GBP [PAYMENTREQUEST_0_DESC] => Order 6 at xxx [PAYMENTREQUEST_0_PAYMENTACTION] => sale [LOCALECODE] => en_GB [PAGESTYLE] => paypal [SOLUTIONTYPE] => Sole [LANDINGPAGE] => Billing [BRANDNAME] => xxx [TOTALTYPE] => Estimated Total [L_PAYMENTREQUEST_0_NAME0] => GSM/3G Modem Kit (Voice & Data) [L_PAYMENTREQUEST_0_AMT0] => 294.00 [L_PAYMENTREQUEST_0_QTY0] => 1 [L_PAYMENTREQUEST_0_TAXAMT0] => 0.00 [PAYMENTREQUEST_0_SHIPPINGAMT] => 0.00 [PAYMENTREQUEST_0_TAXAMT] => 0.00 ) \n\n Array ( [TIMESTAMP] => 2012-11-06T10:47:20Z [CORRELATIONID] => 6d546e6e158b1 [ACK] => Failure [VERSION] => 88.0 [BUILD] => 4181146 [L_ERRORCODE0] => 10413 [L_SHORTMESSAGE0] => Transaction refused because of an invalid argument. See additional error messages for details. [L_LONGMESSAGE0] => The totals of the cart item amounts do not match order amounts. [L_SEVERITYCODE0] => Error )

When I switch VAT off for Drupal commerce everything works fine here.

Also one other thing that confused me, you send over the billing address which is imediately inserted into the credit card billing details which is fine. If you then change to use a paypal account this address is then used as the Shipping address which of course may be different, as specified on my site. Is this a bug?