But for some reason Exim in your server is trying to do local delivery.
Is the DNS Zone for domain.com in your server?
No, DNS zone for domain.com is not on my server, it never has been.
Following is the complete log
#echo "Subject: sendmail test" | sendmail -v
[email protected]
LOG: MAIN
cwd=/root 3 args: sendmail -v
[email protected]
LOG: MAIN
<=
[email protected] U=root P=local S=296 T="sendmail test"
[
[email protected] ~]# LOG: MAIN
cwd=/var/spool/exim 4 args: /usr/sbin/exim -v -Mc 1moq7t-0008Fs-Ne
delivering 1moq7t-0008Fs-Ne
Connecting to mx00.1and1.co.uk [113.111.11.11]:25 ... connected
SMTP<< 220 kundenserver.de (mxeue010) Nemesis ESMTP Service ready
SMTP>> EHLO ns512222.ip-123-49-15.net
SMTP<< 250-kundenserver.de Hello ns512222.ip-123-49-15.net [111.11.11.11]
250-8BITMIME
250-SIZE 157286400
250 STARTTLS
SMTP>> STARTTLS
SMTP<< 220 OK
LOG: MAIN
[113.111.11.11] SSL verify error: certificate name mismatch: DN="/C=DE/O=IONOS SE/ST=Rheinland-Pfalz/L=Montabaur/CN=mx.kundenserver.de" H="mx00.1and1.co.uk"
SMTP>> EHLO ns512222.ip-123-49-15.net
SMTP<< 250-kundenserver.de Hello ns512222.ip-123-49-15.net [111.11.11.11]
250-8BITMIME
250 SIZE 157286400
SMTP>> MAIL FROM:<
[email protected]> SIZE=1328
SMTP<< 550-Requested action not taken: mailbox unavailable
550 invalid DNS MX or A/AAAA resource record
SMTP>> QUIT
SMTP(close)>>
LOG: MAIN
**
[email protected] R=lookuphost T=remote_smtp H=mx00.1and1.co.uk [113.111.11.11] X=TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no: SMTP error from remote mail server after MAIL FROM:<
[email protected]> SIZE=1328: 550-Requested action not taken: mailbox unavailable\n550 invalid DNS MX or A/AAAA resource record
LOG: MAIN
cwd=/var/spool/exim 8 args: /usr/sbin/exim -v -t -oem -oi -f <> -E1moq7t-0008Fs-Ne
LOG: MAIN
<= <> R=1moq7t-0008Fs-Ne U=mailnull P=local S=1848 T="Mail delivery failed: returning message to sender"
LOG: MAIN
Completed
LOG: MAIN
cwd=/var/spool/exim 4 args: /usr/sbin/exim -v -Mc 1moq7u-0008G6-UG
delivering 1moq7u-0008G6-UG
LOG: MAIN
Sender identification U=mailnull D=-system- S=mailnull
Connecting to mx00.1and1.co.uk [113.111.11.11]:25 ... connected
SMTP<< 220 kundenserver.de (mxeue010) Nemesis ESMTP Service ready
SMTP>> EHLO ns512222.ip-123-49-15.net
SMTP<< 250-kundenserver.de Hello ns512222.ip-123-49-15.net [111.11.11.11]
250-8BITMIME
250-SIZE 157286400
250 STARTTLS
SMTP>> STARTTLS
SMTP<< 220 OK
LOG: MAIN
[113.111.11.11] SSL verify error: certificate name mismatch: DN="/C=DE/O=IONOS SE/ST=Rheinland-Pfalz/L=Montabaur/CN=mx.kundenserver.de" H="mx00.1and1.co.uk"
SMTP>> EHLO ns512222.ip-123-49-15.net
SMTP<< 250-kundenserver.de Hello ns512222.ip-123-49-15.net [111.11.11.11]
250-8BITMIME
250 SIZE 157286400
SMTP>> MAIL FROM:<> SIZE=2926
SMTP<< 250 Requested mail action okay, completed
SMTP>> RCPT TO:<
[email protected]>
SMTP<< 250 OK
SMTP>> DATA
SMTP<< 354 Start mail input; end with <CRLF>.<CRLF>
SMTP>> writing message and terminating "."
SMTP<< 250 Requested mail action okay, completed: id=1N9eg1-1md2UA3EWL-015Uwb
SMTP>> QUIT
SMTP(close)>>
LOG: MAIN
=>
[email protected] <
[email protected]> R=dkim_lookuphost T=dkim_remote_smtp H=mx00.1and1.co.uk [113.111.11.11] X=TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no C="250 Requested mail action okay, completed: id=1N9eg1-1md2UA3EWL-015Uwb"
LOG: MAIN
Completed