Why did I get API error code 10747?
PayPal returned API error code 10747 - Invalid Data -This transaction cannot be processed without a valid IP address.
Cause
As part of the DirectPayment API request, PayPal requires merchants to capture and send the buyer's IP address. This error occurs because the IP address is in an invalid format.
Solution
Check the IP address and make sure it is in the IPv4 format, using the dotted decimal notation of four integers, each ranging from 0 to 255. An example of an IP address in IPv4 format would be 123.156.123.156.
IPv6-format IP addresses aren't currently supported.
See the Developer Portal for a complete list of NVP/SOAP API error codes.