I have this problem.
User A@smartermaildomain.com send message to user B@externaldomain.com. this B user have setup out of office reply. User A got mail from System Administrator with Delivery Failure where is (in the spool-> 600 Failed to connect to the recipients mail server):
Could not deliver message to the following recipient(s):
Failed Recipient: cmdspc: false
Reason: Failed to connect to the recipients mail server. No DNS information was found for the 'cmdspc: false' domain.
-- The header and top 20 lines of the message follows --
after header there is out of office message from User B
All IN/OUT mails and outbound out of office are fine, just i have problem with inbound out of office messages.
Thank you for advice where or what i have wrong.