You may see this message when you are doing a manual transmission.
This is because the IP address is used in the Submission Service URL (on the Communications tab) instead of the DNS name of "paymentservices.bacs.co.uk".
Because Voca uses multiple IP addresses for "paymentservices.bacs.co.uk", you may not be connecting to the IP address in your URL. This is not a problem and you can ignore this message.