title: recipient server did not accept our requests to connect. Learn more at https://support.google.com/mail/answer/7720
body: <p>We are able to sent/receive mail to all domains but can't receive mail from Gmail. We are used <strong>postfix, dovecot</strong> on centos 6 servers.These are the mail error logs on the centos 6</p>
  
  <pre><code>May  2 05:51:12 ip-172-31-14-2 postfix/smtpd[25021]: connect from mail-wm1-f52.google.com[209.85.128.52]
  May  2 05:51:12 ip-172-31-14-2 postfix/smtpd[25021]: lost connection after STARTTLS from mail-wm1-f52.google.com[209.85.128.52]
  May  2 05:51:12 ip-172-31-14-2 postfix/cleanup[25023]: 8CBDA80058: message-id=&lt;20190502055112.8CBDA80058@mail.portperrylamaze.com&gt;
  May  2 05:51:12 ip-172-31-14-2 postfix/qmgr[25000]: 8CBDA80058: from=&lt;double-bounce@mail.portperrylamaze.com&gt;, size=953, nrcpt=1 (queue active)
  May  2 05:51:12 ip-172-31-14-2 postfix/smtpd[25021]: disconnect from mail-wm1-f52.google.com[209.85.128.52]
  May  2 05:51:12 ip-172-31-14-2 postfix/cleanup[25023]: D2A6780074: message-id=&lt;20190502055112.8CBDA80058@mail.portperrylamaze.com&gt;
  May  2 05:51:12 ip-172-31-14-2 postfix/qmgr[25000]: D2A6780074: from=&lt;double-bounce@mail.portperrylamaze.com&gt;, size=1108, nrcpt=1 (queue active)
  May  2 05:51:12 ip-172-31-14-2 postfix/local[25028]: 8CBDA80058: to=&lt;postmaster@mail.portperrylamaze.com&gt;, orig_to=&lt;postmaster&gt;, relay=local, delay=0.33, delays=0.28/0/0/0.04, dsn=2.0.0, status=sent (forwarded as D2A6780074)
  May  2 05:51:12 ip-172-31-14-2 postfix/qmgr[25000]: 8CBDA80058: removed
  May  2 05:51:13 ip-172-31-14-2 postfix/pipe[25033]: D2A6780074: to=&lt;postmaster@portperrylamaze.com&gt;, orig_to=&lt;postmaster&gt;, relay=dovecot, delay=0.27, delays=0.04/0/0/0.23, dsn=2.0.0, status=sent (delivered via dovecot service)
  May  2 05:51:13 ip-172-31-14-2 postfix/qmgr[25000]: D2A6780074: removed
  May  2 05:51:17 ip-172-31-14-2 postfix/smtpd[25021]: connect from unknown[141.98.80.33]
  May  2 05:51:17 ip-172-31-14-2 postfix/smtpd[25021]: connect from unknown[141.98.80.33]
  May  2 05:51:20 ip-172-31-14-2 postfix/smtpd[25021]: warning: unknown[141.98.80.33]: SASL PLAIN authentication failed:
  May  2 05:51:20 ip-172-31-14-2 postfix/smtpd[25021]: lost connection after AUTH from unknown[141.98.80.33]
  May  2 05:51:20 ip-172-31-14-2 postfix/smtpd[25021]: disconnect from unknown[141.98.80.33]
  May  2 05:51:20 ip-172-31-14-2 postfix/smtpd[25021]: connect from unknown[141.98.80.33]
  May  2 05:51:24 ip-172-31-14-2 postfix/smtpd[25086]: warning: cannot get RSA certificate from file &lt;/etc/pki/dovecot/certs/dovecot.pem: disabling TLS support
  May  2 05:51:24 ip-172-31-14-2 postfix/smtpd[25086]: warning: TLS library problem: 25086:error:02001002:system library:fopen:No such file or directory:bss_file.c:398:fopen('&lt;/etc/pki/dovecot/certs/dovecot.pem','r'):
  May  2 05:51:24 ip-172-31-14-2 postfix/smtpd[25086]: warning: TLS library problem: 25086:error:20074002:BIO routines:FILE_CTRL:system lib:bss_file.c:400:
  May  2 05:51:24 ip-172-31-14-2 postfix/smtpd[25086]: warning: TLS library problem: 25086:error:140DC002:SSL routines:SSL_CTX_use_certificate_chain_file:system lib:ssl_rsa.c:722:
  May  2 05:51:24 ip-172-31-14-2 postfix/smtpd[25086]: connect from unknown[165.227.46.130]
  </code></pre>