Hello, please check whether the server's port 25 communicates normally, and the normal communication of port 25 is required to send mail.

    kohestanimahdi No, no, it just shows that it doesn't work when the system shows that it runs. You must be able to communicate with it. For example, telnet ipaddress 25 can communicate.

        aaPanel_thisyear Hello,
        No, when I try to send mail, mail returns to my inbox. I check spam and trash in the receiver's email address.

        I can receive email from my google email, but can not send any mail

            10 days later

            I am having same issue. I can receive email, but cannot send them I don't get any error as reply, but it just shows a pop up this error:

            "Some cloud vendors (such as Google, Amazon) close port 25 by default, and you need to contact the vendor to open port 25 before you can use the post office service normally"

            However, I check Port 25 is open and communicating and I am also running ubuntu

              kohestanimahdi
              Please follow the tips of mailtest to improve your information. If your email score is too low, it may be rejected by other inboxes or put in the trash.

                2 months later
                a year later

                aaP_toolzneeded456
                Hello, please describe your problem in detail. If the server cannot connect to port 25 of other servers, check whether the server provider has disabled port 25

                  12 days later

                  Some cloud vendors (such as Google, Amazon) close port 25 by default, and you need to contact the vendor to open port 25 before you can use the post office service normally please help

                    aaP_ssquadram
                    hi,
                    We can't solve this problem. It is recommended to contact the server provider
                    Or use smtp trunk

                      10 days later

                      I am also face same problem, I received mails but unable to send mail is anybody here to help me

                        Dear @"aaPanel_Kern" I am using aapanel server My server received mail from other mail but when I try to send mail outside, this shows your message sent successfully but the mail could not reach the given address.

                        Nov 25 05:33:11 webcarehouse postfix/smtpd[27757]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:19 webcarehouse postfix/smtpd[27751]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                        Nov 25 05:33:19 webcarehouse postfix/smtpd[27751]: connect from unknown[87.246.7.78]
                        Nov 25 05:33:20 webcarehouse postfix/smtpd[28724]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: Connection lost to authentication server
                        Nov 25 05:33:20 webcarehouse postfix/smtpd[28724]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:22 webcarehouse postfix/smtpd[27600]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                        Nov 25 05:33:22 webcarehouse postfix/smtpd[27600]: connect from unknown[87.246.7.227]
                        Nov 25 05:33:29 webcarehouse postfix/smtpd[27600]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:29 webcarehouse postfix/smtpd[27751]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:29 webcarehouse postfix/smtpd[27751]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:30 webcarehouse postfix/smtpd[27600]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:37 webcarehouse postfix/smtpd[27757]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                        Nov 25 05:33:37 webcarehouse postfix/smtpd[27757]: connect from unknown[87.246.7.227]
                        Nov 25 05:33:38 webcarehouse postfix/smtpd[28724]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                        Nov 25 05:33:38 webcarehouse postfix/smtpd[28724]: connect from unknown[87.246.7.78]
                        Nov 25 05:33:39 webcarehouse postfix/smtpd[27751]: connect from unknown[141.98.10.153]
                        Nov 25 05:33:39 webcarehouse postfix/smtpd[27751]: disconnect from unknown[141.98.10.153] quit=1 commands=1
                        Nov 25 05:33:43 webcarehouse dovecot: auth: Warning: auth client 0 disconnected with 1 pending requests: Connection reset by peer
                        Nov 25 05:33:48 webcarehouse postfix/smtpd[27757]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:49 webcarehouse postfix/smtpd[27600]: connect from unknown[141.98.10.153]
                        Nov 25 05:33:49 webcarehouse postfix/smtpd[28724]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:49 webcarehouse postfix/smtpd[27757]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:50 webcarehouse postfix/smtpd[28724]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:52 webcarehouse postfix/smtpd[27751]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                        Nov 25 05:33:52 webcarehouse postfix/smtpd[27751]: connect from unknown[87.246.7.227]
                        Nov 25 05:33:55 webcarehouse postfix/smtpd[27600]: warning: unknown[141.98.10.153]: SASL LOGIN authentication failed: UGFzc3dvcmQ6

                        Dear @aaPanel_Kern I am using aapanel server My server received mail from other mail but when I try to send mail outside, this shows your message sent successfully but the mail could not reach the given address.

                        Nov 25 05:33:11 webcarehouse postfix/smtpd[27757]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:19 webcarehouse postfix/smtpd[27751]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                        Nov 25 05:33:19 webcarehouse postfix/smtpd[27751]: connect from unknown[87.246.7.78]
                        Nov 25 05:33:20 webcarehouse postfix/smtpd[28724]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: Connection lost to authentication server
                        Nov 25 05:33:20 webcarehouse postfix/smtpd[28724]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:22 webcarehouse postfix/smtpd[27600]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                        Nov 25 05:33:22 webcarehouse postfix/smtpd[27600]: connect from unknown[87.246.7.227]
                        Nov 25 05:33:29 webcarehouse postfix/smtpd[27600]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:29 webcarehouse postfix/smtpd[27751]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:29 webcarehouse postfix/smtpd[27751]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:30 webcarehouse postfix/smtpd[27600]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:37 webcarehouse postfix/smtpd[27757]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                        Nov 25 05:33:37 webcarehouse postfix/smtpd[27757]: connect from unknown[87.246.7.227]
                        Nov 25 05:33:38 webcarehouse postfix/smtpd[28724]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                        Nov 25 05:33:38 webcarehouse postfix/smtpd[28724]: connect from unknown[87.246.7.78]
                        Nov 25 05:33:39 webcarehouse postfix/smtpd[27751]: connect from unknown[141.98.10.153]
                        Nov 25 05:33:39 webcarehouse postfix/smtpd[27751]: disconnect from unknown[141.98.10.153] quit=1 commands=1
                        Nov 25 05:33:43 webcarehouse dovecot: auth: Warning: auth client 0 disconnected with 1 pending requests: Connection reset by peer
                        Nov 25 05:33:48 webcarehouse postfix/smtpd[27757]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:49 webcarehouse postfix/smtpd[27600]: connect from unknown[141.98.10.153]
                        Nov 25 05:33:49 webcarehouse postfix/smtpd[28724]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                        Nov 25 05:33:49 webcarehouse postfix/smtpd[27757]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:50 webcarehouse postfix/smtpd[28724]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                        Nov 25 05:33:52 webcarehouse postfix/smtpd[27751]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                        Nov 25 05:33:52 webcarehouse postfix/smtpd[27751]: connect from unknown[87.246.7.227]
                        Nov 25 05:33:55 webcarehouse postfix/smtpd[27600]: warning: unknown[141.98.10.153]: SASL LOGIN authentication failed: UGFzc3dvcmQ6

                          aaP_iamshoaib216
                          Prompt: SASL LOGIN authentication failed
                          Check whether the email account password is correct. You are advised to reset the password once

                            Dear @aaPanel_Kern I have reset the mail password and tried to send it again but face the same issue My server allows me to send mail on another mail present on the same server, but don't send mail outside the server other mails. Kindly check the logs I have attached below and inform me. I shall be very thankful to you for your kindness.

                            Nov 26 08:45:53 webcarehouse postfix/cleanup[53293]: 4CC8A42190D: message-id=-------------@webcare.localdomain
                            Nov 26 08:45:53 webcarehouse postfix/qmgr[2317]: 4CC8A42190D: from=info@mail.com, size=765, nrcpt=1 (queue active)
                            Nov 26 08:45:56 webcarehouse postfix/bounce[53557]: warning: /etc/postfix/main.cf, line 68: overriding earlier entry: relayhost=
                            Nov 26 08:45:56 webcarehouse postfix/smtp[53169]: 4CC8A42190D: to=mail@gmail.com, relay=smtp.mailgun.org[34.150.216.144]:587, delay=3.3, delays=0.22/0/2.6/0.42, dsn=4.0.0, status=deferred (host smtp.mailgun.org[34.150.216.144] said: 421 Domain sandbox06091835221a4bdba1b37e3cad48d674.mailgun.org is not allowed to send: Sandbox subdomains are for test purposes only. Please add your own domain or add the address to authorized recipients in Account Settings. (in reply to DATA command))
                            Nov 26 08:45:58 webcarehouse postfix/smtpd[51426]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                            Nov 26 08:45:59 webcarehouse postfix/smtpd[51426]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:00 webcarehouse postfix/smtpd[50130]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                            Nov 26 08:46:01 webcarehouse postfix/smtpd[50130]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:02 webcarehouse postfix/smtpd[52998]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                            Nov 26 08:46:02 webcarehouse postfix/smtpd[52998]: connect from unknown[87.246.7.78]
                            Nov 26 08:46:05 webcarehouse postfix/smtpd[51426]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                            Nov 26 08:46:05 webcarehouse postfix/smtpd[51426]: connect from unknown[87.246.7.227]
                            Nov 26 08:46:12 webcarehouse postfix/smtpd[50743]: disconnect from localhost[127.0.0.1] ehlo=1 auth=1 mail=1 rcpt=1 data=1 commands=5
                            Nov 26 08:46:19 webcarehouse postfix/smtpd[51426]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[50130]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[50130]: connect from unknown[87.246.7.227]
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[52998]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[51426]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[52998]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[50743]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                            Nov 26 08:46:20 webcarehouse postfix/smtpd[50743]: connect from unknown[87.246.7.78]
                            Nov 26 08:46:32 webcarehouse postfix/smtpd[50130]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: Connection lost to authentication server
                            Nov 26 08:46:33 webcarehouse postfix/smtpd[50130]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:35 webcarehouse postfix/smtpd[51426]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                            Nov 26 08:46:35 webcarehouse postfix/smtpd[51426]: connect from unknown[87.246.7.227]
                            Nov 26 08:46:35 webcarehouse postfix/smtpd[50743]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: Connection lost to authentication server
                            Nov 26 08:46:37 webcarehouse postfix/smtpd[50743]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:39 webcarehouse postfix/smtpd[52998]: warning: hostname net6-ip78.linkbg.com does not resolve to address 87.246.7.78: Name or service not known
                            Nov 26 08:46:39 webcarehouse postfix/smtpd[52998]: connect from unknown[87.246.7.78]
                            Nov 26 08:46:41 webcarehouse postfix/smtpd[51426]: warning: unknown[87.246.7.227]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                            Nov 26 08:46:42 webcarehouse postfix/smtpd[51426]: disconnect from unknown[87.246.7.227] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:50 webcarehouse postfix/smtpd[50130]: warning: hostname net6-ip227.linkbg.com does not resolve to address 87.246.7.227: Name or service not known
                            Nov 26 08:46:50 webcarehouse postfix/smtpd[50130]: connect from unknown[87.246.7.227]
                            Nov 26 08:46:50 webcarehouse postfix/smtpd[52998]: warning: unknown[87.246.7.78]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
                            Nov 26 08:46:52 webcarehouse postfix/smtpd[52998]: disconnect from unknown[87.246.7.78] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
                            Nov 26 08:46:52 webcarehouse dovecot: auth: Warning: auth client 0 disconnected with 1 pending requests: Connection reset by peer

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