Payflow Pro integration

Hi, I'm trying to set up a form with Payflow Pro payment. I have entered the Paypal API credentials several times, even pasting them into Notepad first before copying them into Jotform settings, and I continue to get the following error when attempting to verify the integration:

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Unable to Verify

Invalid Configuration -- This transaction cannot be processed due to an invalid merchant configuration.

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Hope you can help.

Please contact your PayPal support to make sure there is nothing wrong in your account, that is preventing the authentication of your PayPal Pro credentials.