Question : 421 4.3.2 Service not available, closing transmission channel

I use EasyMail and now for about a week my easymail log shows this error

"421 4.3.2 Service not available, closing transmission channel"

The easmail is offsite but the other pc's running it on site work...

Answer : 421 4.3.2 Service not available, closing transmission channel

verify that the server is listening on the correct ip address with port 25
attempt a telnet session on port 25