System I/O error (in reply to end of DATA command) for LMTP delivery

[Ken Murchison]

On 6/1/18 12:21 PM, Stephen Ingram wrote:
> I'm receiving a 451 4.3.0 System I/O error (in reply to end of DATA 
> command) error from Postfix when trying to deliver to cyrus-imap and 
> not really sure why. I'm on CentOS 7 (2.4.17-8) after downgrading from 
> current version. I'm using Kerberos GSSAPI to connect to the front 
> end, but authentication appears to be working fine as I can see 
> authenticated when enabling LMTP debugging in Postifx. All messages 
> are refused for delivery though. I'm not sure what to do. Any suggestions?

Any chance that Kerberos is negotiating a security layer?

-- 
Kenneth Murchison
Cyrus Development Team
FastMail Pty Ltd