I tried uninstalling mail server and installing it back but still the same problem
here is the log

Nov 10 10:53:55 vmi483884 postfix/smtpd[17238]: warning: hostname net6-ip228.linkbg.com does not resolve to address 87.246.7.228: Name or service not known
Nov 10 10:53:55 vmi483884 postfix/smtpd[17238]: connect from unknown[87.246.7.228]
Nov 10 10:53:57 vmi483884 postfix/smtpd[17238]: disconnect from unknown[87.246.7.228] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Nov 10 10:54:34 vmi483884 postfix/smtpd[17238]: warning: hostname net6-ip228.linkbg.com does not resolve to address 87.246.7.228: Name or service not known
Nov 10 10:54:34 vmi483884 postfix/smtpd[17238]: connect from unknown[87.246.7.228]
Nov 10 10:54:38 vmi483884 postfix/smtpd[17238]: disconnect from unknown[87.246.7.228] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Nov 10 10:55:14 vmi483884 postfix/smtpd[17238]: warning: hostname net6-ip228.linkbg.com does not resolve to address 87.246.7.228: Name or service not known
Nov 10 10:55:14 vmi483884 postfix/smtpd[17238]: connect from unknown[87.246.7.228]
Nov 10 10:55:18 vmi483884 postfix/smtpd[17238]: disconnect from unknown[87.246.7.228] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Nov 10 10:55:53 vmi483884 postfix/smtpd[17238]: warning: hostname net6-ip228.linkbg.com does not resolve to address 87.246.7.228: Name or service not known
Nov 10 10:55:53 vmi483884 postfix/smtpd[17238]: connect from unknown[87.246.7.228]
Nov 10 10:55:57 vmi483884 postfix/smtpd[17238]: disconnect from unknown[87.246.7.228] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Nov 10 10:55:57 vmi483884 postfix/postfix-script[17850]: stopping the Postfix mail system
Nov 10 10:55:57 vmi483884 postfix/master[12864]: terminating on signal 15
Nov 10 10:55:58 vmi483884 postfix/postfix-script[17962]: starting the Postfix mail system
Nov 10 10:55:58 vmi483884 postfix/master[17964]: fatal: bind 0.0.0.0 port 465: Address already in use
Nov 10 10:55:59 vmi483884 postfix/master[17963]: fatal: daemon initialization failure
Nov 10 10:56:00 vmi483884 postfix/postfix-script[17965]: fatal: mail system startup failed
Nov 10 10:56:05 vmi483884 dovecot: master: Dovecot v2.2.33.2 (d6601f4ec) starting up for imap, pop3, lmtp (core dumps disabled)
Nov 10 10:56:10 vmi483884 dovecot: master: Warning: Killed with signal 15 (by pid=18078 uid=0 code=kill)
Nov 10 10:56:10 vmi483884 postfix/postfix-script[18187]: starting the Postfix mail system
Nov 10 10:56:10 vmi483884 postfix/master[18189]: fatal: bind 0.0.0.0 port 465: Address already in use
Nov 10 10:56:10 vmi483884 dovecot: master: Dovecot v2.2.33.2 (d6601f4ec) starting up for imap, pop3, lmtp (core dumps disabled)
Nov 10 10:56:11 vmi483884 postfix/master[18188]: fatal: daemon initialization failure
Nov 10 10:56:12 vmi483884 postfix/postfix-script[18204]: fatal: mail system startup failed
Nov 10 10:56:52 vmi483884 postfix/postfix-script[18382]: starting the Postfix mail system
Nov 10 10:56:52 vmi483884 postfix/master[18384]: fatal: bind 0.0.0.0 port 465: Address already in use
Nov 10 10:56:53 vmi483884 postfix/master[18383]: fatal: daemon initialization failure
Nov 10 10:56:54 vmi483884 postfix/postfix-script[18385]: fatal: mail system startup failed
Nov 10 10:57:32 vmi483884 postfix/postfix-script[19306]: starting the Postfix mail system
Nov 10 10:57:32 vmi483884 postfix/master[19308]: daemon started -- version 3.3.0, configuration /etc/postfix
Nov 10 10:57:41 vmi483884 postfix/postfix-script[19637]: stopping the Postfix mail system
Nov 10 10:57:41 vmi483884 postfix/master[19308]: terminating on signal 15
Nov 10 10:57:41 vmi483884 postfix/postfix-script[19749]: starting the Postfix mail system
Nov 10 10:57:41 vmi483884 postfix/master[19751]: fatal: bind 0.0.0.0 port 465: Address already in use
Nov 10 10:57:42 vmi483884 postfix/master[19750]: fatal: daemon initialization failure
Nov 10 10:57:43 vmi483884 postfix/postfix-script[19752]: fatal: mail system startup failed