aaPanel_Kern
the server rDNS is showing on my vps panel.
so how will I configure it on the aapanel to resolve with my mail server?

      mac_dolar
      Refer to this article. You need the help of a server provider or network provider
      https://en.wikipedia.org/wiki/Reverse_DNS_lookup

          aaPanel_Kern
          why I can send email from the webmail, but I can't send mail using SMTP, its shows this error below
          I have tried connecting using port 25, 587, 465 and yet the same error.. the domain.com is used to reference my domain name.

          Server: mail.domain.com
          User: user@domail.com
          Result: FAILED, code 3016: Failed to send command.

          Transcript:

          220 mail.domain.com ESMTP Postfix

          EHLO mail.domain.com
          250-mail.domain.com
          250-PIPELINING
          250-SIZE 102400000
          250-VRFY
          250-ETRN
          250-STARTTLS
          250-AUTH PLAIN LOGIN
          250-ENHANCEDSTATUSCODES
          250-8BITMIME
          250-DSN
          250-SMTPUTF8
          250 CHUNKING
          STARTTLS
          220 2.0.0 Ready to start TLS
          SSL negotiation failed, code 1: SSL module internal error.
          error:14077438:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert internal error
          AUTH LOGIN
          Failed to send command

          Operation completed: 10/27/2022 5:16:53 p.m.
          Elapsed time: 1.1 seconds

          1) Please what could be the problem?
          2) if possible, please can you give me your email address let me send you my panel login details so that you help me and configure the aapanel mailserver?

          thank you.

              mac_dolar
              Hello, please try to reapply for SSLs at the mail server. At the same time, check the postfix configuration, which can be viewed in the server status
              "mail.135mailtest.com" is replaced with your domain name
              Put:
              smtpd_tls_chain_files=/etc/ssl/private/ssl-cert-snakeoil.key,/etc/ssl/certs/ssl-cert-snakeoil.pem
              Change to:
              smtpd_tls_chain_files = /www/server/panel/plugin/mail_sys/cert/135mailtest.com/privkey.pem,/www/server/panel/plugin/mail_sys/cert/135mailtest.com/fullchain.pem
              Note to replace 135mailtest.com with your domain name.
              Also check /www/server/panel/plugin/mail_sys/cert/135mailtest.com/ for privkey.pem and fullchain.pem files
              You can use this command to check whether the correct SSL is configured
              openssl s_client -connect mail.135mailtest.com:587 -starttls smtp
              or
              openssl s_client -connect mail.135mailtest.com:465 -starttls smtp

                  aaPanel_Kern
                  please where can I locate this file below you said I should modify?
                  smtpd_tls_chain_files=/etc/ssl/private/ssl-cert-snakeoil.key,/etc/ssl/certs/ssl-cert-snakeoil.pem

                  I have tried to configure the mailserver many times, but it keeps on not working properly.
                  Please wouldn't it be better I give you me aapanel login details so that you help me and configure the postfix mailserver?

                  thank you.

                      mac_dolar
                      Hi, can you give us your aapanel information? The server makes a snapshot backup first, if possible, please send it to kern@aapanel.com.
                      It is recommended to fill in the following
                      Post link:
                      SSH IP address, account password and port:
                      aapanel login link address and account password:

                      No post link will not be able to know which user's information is

                          aaPanel_Kern
                          Please check the email, I have sent you the all the server information you requested.

                          Please let me know once the issue is solved!
                          Thank you so much.

                            10 months later

                            Hi, please check if mysql is running? can be found in the app store
                            Please check whether the database interface can add a test database?
                            Please check whether the user and password configured on the website are correct?

                            kloudboy

                              a year later
                              a month later

                              aaPanel_Jose I have tried your method. But after changing password, use can;t login to roubcube webmal anymore. Login failed.