I'm trying to set up my website store with Paypal, I've installed the standard and express Paypal plugins. When I try to test purchase my own product I get this message after checking out and inputting my card into Paypal to finalize payment.
Not Acceptable!
An appropriate representation of the requested resource could not be found on this server. This error was generated by Mod_Security.
This error doesn't seem to be a PayPal error. It seems that the error message you mentioned is due to the Security Mod on the site that you've got set up. This might either be blocking the call to PayPal from happening or blocking the response from PayPal from showing correctly because the Security Plugin things it is a malicious object response.
If this is WooCommerce or a similar eCommerce system, I would recommend speaking with their support team to understand why this error would get thrown.
