Mail Queue backing up

[Sniffer]

Mail seem to come in fine but can't seem to send any. I'm also not getting mails from the server they are all in mail queue.

After running sh /script/sysinfo this is what I have.

A. Kloxo-MR: 7.0.0.b-2015103001
   - Web: hiawatha-9.15.0-f.6.mr.el6.x86_64
   - PHP: php54s-5.4.45-1.ius.el6 (cgi mode)
B. Plateform:
   - OS: CentOS release 6.7 (Final) x86_64
   - Hostname: server2.domain.com
C. Services:
   1. MySQL: MariaDB-server-10.0.22-1.el6.x86_64
   2. PHP:
      - Branch: php54-cli-5.4.45-1.ius.el6.x86_64
      - Multiple:
        * php53m-5.3.29-1.ius.el6
        * php54m-5.4.45-1.ius.el6
        * php55m-5.5.30-1.ius.el6
      - Used: php55m
   3. Httpd: httpd-2.2.31-1.mr.el6.x86_64
      - PHP Type: php-fpm_event
   4. Lighttpd: --uninstalled--
   5. Hiawatha: --unused--
   6. Nginx: --uninstalled--
   7. Cache: --uninstalled--
   8. Dns: bind-9.9.7-1.mr.el6.x86_64
   9. Qmail: qmail-toaster-1.03-1.3.55.mr.el6.x86_64
      - with: courier-imap-toaster-4.1.2-1.3.18.mr.el6.x86_64
D. Memory:
                total       used       free     shared    buffers     cached
   Mem:          3830       1073       2757          1         30        610
   -/+ buffers/cache:        431       3398
   Swap:         1023          0       1023
E. Disk Space:
   Filesystem      Size  Used Avail Use% Mounted on
   /dev/vda1        78G  3.2G   71G   5% /

[MRatWork]

Try delete mail in 'mailqueue' with 'sh /script/mailqueue -D'.

Do you have 'domain.com' as your real domain?. Use one of your domain as base of hostname.

[Sniffer]

I have deleted all mail in queue although none got delivered.

No I'm not using domain.com not wanting to show my own domain!

[MRatWork]

inform here 'cat /etc/resolv.conf'.

[Sniffer]

inform here 'cat /etc/resolv.conf'.

nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844

[Sniffer]

So I guess this is causing my issue from the mail queue logs.

deferral: CNAME_lookup_failed_temporarily._(#4.4.3)

Has anyone else had or having this issue as I can't get emails working.

[MRatWork]

Maybe related to dns setting where no cname for mail.

[Sniffer]

Some emails are getting delivered but always to spam even thought SPF & DKIM is all set correct. Server emails never seem to get delivered as they just sit in the mail queue and after a while says failure notice.

[Sniffer]

Seeing this in mail log now. Even though the email address is correct!

Nov 23 17:20:38 server2 send: delivery 206: failure: User_and_password_not_set,_continuing_without_authentication./154.34.342.201_does_not_like_recipient./Remote_host_said:_550_No_such_person_at_this_address./Giving_up_on_154.34.342.201./