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