SMTP Server error

[stla]

Suddenly my mail server (Linux IMAP)will not allow mw to send mails (see following error) nor are incoming mails being shown.
Can anyone advise?
Best regards.

An unknown error has occurred. Subject 'Test', Account: 'mail.walterdigital.de',
Server: 'mail.walterdigital.de', Protocol: SMTP, Server Response: '451 4.7.1 Please
try again later', Port: 25, Secure(SSL): No, Server Error: 451, Error Number:
0x800CCC6A

 

[RhythmAce]

The 451 error means that the sender's address doesn't resolve. Have you made any changes to your network? Did your isp change your ip address? Is your "MX" record current?

 

[stla]

All I have done is restrt the machine.

I have done an nslook up and got the internal ip address sucessfully.

Also the MX record looks OK:
Your 2 MX records are:
50 mail.walterdigital.de. [TTL=86400] IP=62.8.219.22 [TTL=86400]
100 mail2.walterdigital.de. [TTL=86400] IP=62.8.219.21 [TTL=86400]

 

[stla]

Resolved it, the RAV virus license had expired. Removed the programme and it worked!

 

[RhythmAce]

That was gonna be my next guess