Should I use the default or alternate SMTP port settings with the SMTP server?
An increasing number of ISPs are blocking the default SMTP port 25 - to work around this we provide a number of alternative ports that you can use.
If your email program or application supports it (most current versions do) we recommend that you use one of the alternative SMTP ports that we provide:
|25||default / not recommended|
For more details see My ISP blocks SMTP on port 25 - what can I do?