Customer Redirected to Checkout Payment Page

For a while I stopped accepting PayPal on my website.

Then again I had customer that kept asking if we accept PayPal so when I upgraded the store to 1.39 I turned PayPal back on.

I have the Express Checkout on, so customers attempt to checkout using PayPal after they insert all their information and click the Pay button they are being redirected back to the Checkout Payment page. We never receive the payment and the customers PayPal account doesn't show the payment.

Has anybody else faced this problem before?

Another question. Is it possible to activate both the PayPal standard payment and the Express Checkout in 1.39?

I have the Express Checkout on, so customers attempt to checkout using PayPal after they insert all their information and click the Pay button they are being redirected back to the Checkout Payment page.
Enable the logs in the payment module settings and process a test transaction to see wht the logs state
Another question. Is it possible to activate both the PayPal standard payment and the Express Checkout in 1.39?
NO not suggested