my MacAfee firewall seems to be blocking access to 213.171.193.5 can anyone tell me how to list this as a trusted address?
If the McAfee firewall you are using is supplied by BT, BT no longer use the free McAfee product. Customers are now advised that they should move to Norton which is now the BT Virus Protect product offered for free.
See link
What is BT Virus Protect and how do I get it? | BT Help
If it is not part of the BT product you would be better to post your question on the McAfee user forum.