Wherever possible, you should get your email application to connect to mail.smtp2go.com, and not directly connect to an IP address.
However, some email applications like fax machines or printers may ask you to enter an IP address instead of an SMTP server.
If your email application needs to connect to an IP address, please try connecting to an IP address close to you:
North America:
43.228.184.6 or 103.47.204.4
Europe:
103.2.140.82 or 103.2.143.7
Australia:
45.79.238.223 or 172.105.254.10
If you have an outbound firewall that only allows you to connect to particular IP addresses, you'll need to also add this IP address to that firewall.