Unable to send email. Says "server is temp not available"

[CRIA]

Any advise how to fix the following error below so I can send emails?
I'm using Windows Mail.

An unknown error has occurred. Subject 'What's Happening in January?',
Account: 'mail.mchsi.com (1)', Server: 'mail.mchsi.com', Protocol: SMTP,
Server Response: '421 dsmdc-mail-bxga4 bizsmtp ESMTP server temporarily not
available', Port: 25, Secure(SSL): No, Server Error: 421, Error Number:
0x800CCC67

 

[Gary VanderMolen \(MVP\)]

The error message seems quite self-explanatory: "server temporarily
not available." Contact MCHSI tech support for help.
In the meantime you can send via webmail or use a different SMTP
server.