Mail not sending getting error on rainloop: Undelivered Mail Returned to Sender

Hi,

We installed the Cyber panel From Digitalocean, unfortunately no mail are sending out from the server. Getting error message on rainloop " Undelivered Mail Returned to Sender". We also installed the ConfigServer Security & Firewall its log email also not getting. We run grep postfix the out put added below.

Note: Original domain name was renamed or hidden as server.net

root@server:~# journalctl -f | grep postfix
Jun 11 22:31:22 server postfix/submission/smtpd[126326]: connect from localhost[ 127.0.0.1]
Jun 11 22:31:22 server postfix/submission/smtpd[126326]: TLS SNI localhost from localhost[127.0.0.1] not matched, using default chain
Jun 11 22:31:23 server postfix/submission/smtpd[126326]: 24779FEA65: client=loca lhost[127.0.0.1], sasl_method=PLAIN, sasl_username=info@server.net
Jun 11 22:31:23 server postfix/cleanup[126329]: 24779FEA65: message-id=<48922c71 ca2aa78e17db597bf79846ec@server.net>
Jun 11 22:31:23 server postfix/qmgr[125626]: 24779FEA65: from=info@server.net, size=1158, nrcpt=1 (queue active)
Jun 11 22:31:23 server postfix/submission/smtpd[126326]: disconnect from localho st[127.0.0.1] ehlo=2 starttls=1 auth=1 mail=1 rcpt=1 data=1 quit=1 commands=8
Jun 11 22:31:23 server postfix/pipe[126330]: 24779FEA65: to=<info@livecreation.i n>, relay=dovecot, delay=0.09, delays=0.06/0.01/0/0.02, dsn=5.1.1, status=bounce d (user unknown)
Jun 11 22:31:23 server postfix/cleanup[126329]: 394A1FEA72: message-id=<20220611 223123.394A1FEA72@mail.server.net>
Jun 11 22:31:23 server postfix/qmgr[125626]: 394A1FEA72: from=<>, size=3434, nrc pt=1 (queue active)
Jun 11 22:31:23 server postfix/bounce[126332]: 24779FEA65: sender non-delivery n otification: 394A1FEA72
Jun 11 22:31:23 server postfix/qmgr[125626]: 24779FEA65: removed
Jun 11 22:31:23 server postfix/pipe[126330]: 394A1FEA72: to=info@server.net, r elay=dovecot, delay=0.02, delays=0/0/0/0.02, dsn=2.0.0, status=sent (delivered v ia dovecot service)
Jun 11 22:31:23 server postfix/qmgr[125626]: 394A1FEA72: removed

You have space in domain ending info@livecreation.i n check that and make sure you requested DO open port 25.

check postfix status and also port must be opened

Postfix and Dovecote status are showing working fine, we also checked firewall all the ports are open. If we send a mail outside to gmail or other provider it was returning with subject line “Undelivered Mail Returned to Sender” but if we send same domain name other email address it was delivering in side the serve. I don’t know what was the issue. So sad to see it was not working.

Two more day I will try other possible ways other wise i need to go install CWP control panel as it was working fine in our another server and their support plan are very lower than Cyber panel. Totally fedup love to use cyber panel but we faced many issues like website automatically down some time and manully we need to restart OpenLiteSpeed two or three time we need to click on the restart button to work.

See it may happen while we copy the log, Iam assure email address and everything is correct , but not getting an resolution to fix this email delivery.

I think you have port 25 closed by DO. Even you open all ports won’t help when provider blocking it.
Default they blocking port 25 from all users, you need open support ticket and ask them open it.

open ticket with do and ask to open email ports

Here is our output of netstat -tulpen

root@server:~# netstat -tulpen
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State User Inode PID/Program name
tcp 0 0 0.0.0.0:995 0.0.0.0:* LISTEN 0 1234253 183743/dovecot
tcp 0 0 0.0.0.0:9443 0.0.0.0:* LISTEN 0 24643 761/sshd: /usr/sbin
tcp 0 0 0.0.0.0:7080 0.0.0.0:* LISTEN 0 26687 100823/openlitespee
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 112 25734 891/mysqld
tcp 0 0 0.0.0.0:587 0.0.0.0:* LISTEN 0 1235284 183875/master
tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 119 25086 870/redis-server 12
tcp 0 0 127.0.0.1:11211 0.0.0.0:* LISTEN 118 23981 672/memcached
tcp 0 0 0.0.0.0:110 0.0.0.0:* LISTEN 0 1234251 183743/dovecot
tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN 0 1234282 183743/dovecot
tcp 0 0 127.0.0.1:783 0.0.0.0:* LISTEN 0 559342 102874/perl
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 0 26689 100823/openlitespee
tcp 0 0 0.0.0.0:465 0.0.0.0:* LISTEN 0 1235290 183875/master
tcp 0 0 0.0.0.0:53 0.0.0.0:* LISTEN 0 1232238 181800/pdns_server
tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 0 26376 1079/pure-ftpd (SER
tcp 0 0 127.0.0.1:3000 0.0.0.0:* LISTEN 0 24333 678/nghttpx
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 0 1235278 183875/master
tcp 0 0 0.0.0.0:8090 0.0.0.0:* LISTEN 0 512999 96197/lscpd (lscpd
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN 0 26690 100823/openlitespee
tcp 0 0 127.0.0.1:8891 0.0.0.0:* LISTEN 117 24859 805/opendkim
tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN 0 1234284 183743/dovecot
tcp6 0 0 :::995 :::* LISTEN 0 1234254 183743/dovecot
tcp6 0 0 :::9443 :::* LISTEN 0 24649 761/sshd: /usr/sbin
tcp6 0 0 :::587 :::* LISTEN 0 1235285 183875/master
tcp6 0 0 :::110 :::* LISTEN 0 1234252 183743/dovecot
tcp6 0 0 :::143 :::* LISTEN 0 1234283 183743/dovecot
tcp6 0 0 ::1:783 :::* LISTEN 0 559340 102874/perl
tcp6 0 0 :::465 :::* LISTEN 0 1235291 183875/master
tcp6 0 0 :::53 :::* LISTEN 0 1232239 181800/pdns_server
tcp6 0 0 :::21 :::* LISTEN 0 26377 1079/pure-ftpd (SER
tcp6 0 0 :::25 :::* LISTEN 0 1235279 183875/master
tcp6 0 0 :::993 :::* LISTEN 0 1234285 183743/dovecot
udp 0 0 0.0.0.0:50507 0.0.0.0:* 0 513011 96200/lscpd (lscpd
udp 0 0 0.0.0.0:443 0.0.0.0:* 0 26691 100823/openlitespee
udp 0 0 0.0.0.0:7080 0.0.0.0:* 0 26688 100823/openlitespee
udp 0 0 0.0.0.0:52247 0.0.0.0:* 0 539892 100825/openlitespee
udp 0 0 0.0.0.0:53 0.0.0.0:* 0 1232236 181800/pdns_server
udp6 0 0 :::53 :::* 0 1232237 181800/pdns_server

Try: telnet your.mailserver.com 25