If you use a firewall, the relevant eRoaming platform IP addresses must be enabled on your side to receive requests from the HBS. The relevant IP addresses will be forwarded to you through the answer to your ticket of article "Whitelisting of the IP Addresses".
intercharge CPO: Whitelisting of the IP Addresses
intercharge EMP: Whitelisting of the IP Addresses
intercharge Check CPO: Whitelisting of the IP Addresses
intercharge Check EMP: Whitelisting of the IP Addresses