SMTP Failing ...

I am getting the following error:

An unknown error has occurred. Subject ‘Re: The Latest Splash Page’, Account: ‘mail.XXX.com’, Server: ‘mail.XXX.com’, Protocol: SMTP, Server Response: ‘451 qq write error or disk full (#4.3.0)’, Port: 25, Secure(SSL): No, Server Error: 451, Error Number: 0x800CCC6A

I am receiving the same error.

hold on please, yes we are aware of this and it will be corrected very shortly (20 minutes max)