Help to fix email can't receive and send email

I'm using
Ubuntu 16.04
Apache web server
Roundcube

Mail log

Mail error log

System log

 

Thanks can receive email now but the recipient when send email doesn't receive.

 

I tried to send same address in my roundcube I receive the messages. means system is work.
I check my
netstat -tap | grep smtp

Code:

root@nursingcpdunits:~# netstat -tap | grep smtp
tcp        0      0 localhost:10025         *:*                     LISTEN       7542/smtpd
tcp        0      0 *:smtp                  *:*                     LISTEN       7515/smtpd
tcp        0      0 localhost:38732         localhost:mysql         ESTABLISHED  7531/smtp
tcp        0      0 localhost:38734         localhost:mysql         ESTABLISHED  7530/smtp
tcp6       0      0 [::]:smtp               [::]:*                  LISTEN       7515/smtpd

Kindly check my iptables -L

Code:

root@nursingcpdunits:~# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
f2b-dovecot-pop3imap  tcp  --  anywhere             anywhere             multiport dports pop3,pop3s,imap2,imaps
f2b-pureftpd  tcp  --  anywhere             anywhere             multiport dports ftp
f2b-postfix-sasl  tcp  --  anywhere             anywhere             multiport dports smtp
f2b-sshd   tcp  --  anywhere             anywhere             multiport dports ssh

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Chain f2b-dovecot-pop3imap (1 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere

Chain f2b-postfix-sasl (1 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere

Chain f2b-pureftpd (1 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere

Chain f2b-sshd (1 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere
root@nursingcpdunits:~#

Code:

root@nursingcpdunits:~# dig mx nursingcpdunits.com

; <<>> DiG 9.10.3-P4-Ubuntu <<>> mx nursingcpdunits.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33403
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;nursingcpdunits.com.           IN      MX

;; ANSWER SECTION:
nursingcpdunits.com.    300     IN      MX      10 dc-2b1fdaae15cc.nursingcpdunits.com.
nursingcpdunits.com.    300     IN      MX      10 mail.nursingcpdunits.com.

;; ADDITIONAL SECTION:
mail.nursingcpdunits.com. 300   IN      A       45.77.103.247

;; Query time: 3 msec
;; SERVER: 108.61.10.10#53(108.61.10.10)
;; WHEN: Tue Dec 26 08:02:21 UTC 2017
;; MSG SIZE  rcvd: 117

 

I'm using cloudflare kindly check if correct

 

Th

Thank you very much Sir.
The support team now replied to my query

 

Sir Till how to determine if open port 25. The support said "We have removed the default SMTP block on your account."

 

Update: email messages was receive now by the recepient but in spam messages.

 

How should I check Sir Till? thanks