Payment - Paypal! Need help urgently!

Members of my site get this message when trying to buy membership: "This payment cannot be completed and your account has not been charged. Please contact your merchant for more information." "Return to merchant and try a different payment method

We are not able to process your payment using your PayPal account at this time. Please return to the merchant's website and try using a different payment method (if available). "

In this setting paypal are:

There is an example of the easiest configuration.

Active: checked

Mode: live

Business: your PayPal email

Process type: direct

Connection type: HTML

Identity token: leave empty

Sandbox: leave empty

Someone knows what could be the reason?

did you set up IPN in your paypal account?

 I used a direct connection (Process type: direct) without creating an IPN. Earlier this configuration worked on the previous site. And now there is a problem, the cause of which is unknown to me.

i know there have been a lot of persons with issues concerning the paypal - I have always used the IPN (on 5 different sites now) and that way has always worked for me 100%

 You can specify the type of a link to a description of how to carry out the procedure of creating connections to the Paypal method using IPN?

I will be a very Thanksgiving

this is how i have always set mine up - but others have recommended other ways:

Dolphin setting:

• Process type: IPN

PayPal settings:

• Auto Return for Website Payments: Off
• Receive IPN messages (Enabled): On
• Notification URL: http://blah.com/m/payment/act_finalize_checkout/paypal/0