I've changed settings in dnslookup section of exim4 config a few weeks ago and since that time the customers are complaining that some of their e-mails didn't get delivered.
The only thing I've changed in the config file is the errors_to property. I have virtual mailboxes and I want the error messages to be delivered to the virtual sender, so I've changed it to this:
errors_to = ${if def:header_from:{${addresses:$h_from:}}{$sender_address:}}
Can this setting somehow affect the mail headers? How can I fix it to do what I want and not to affect the e-mail message?
The only error I found in the log which could be related is this one:
host mx50.seznam.cz [77.75.77.47]: 503 5.5.4 Only one recipient allowed with empty MAIL FROM address.
