Mac Mail can not send and it’s not a port issue

{ December 4, 2009 @ 2:50 pm } · { Apple }

Look around on the web and you will see plenty of pages saying to change the outgoing mail port number. This can fix many of people’s problems, but sometimes it takes a bit more to fix it.

Here is what I did for a customer and they were able to send out:

Go to: Apple Menu > System
Preferences > Network > Built-In Ethernet > Ethernet TAB > Configure/Manually > Max Packet Size(MTU)/Custon > set to ’1492′ > Apply

After that, my customer was able to send.