on centos 7.

May 6 03:38:41 dumitru postfix/smtp[15881]: connect to gmail-smtp-in.l.google.com[2a00:1450:400c:c00::1b]:25: Connection timed out
May 6 03:39:11 dumitru postfix/smtp[15881]: connect to alt1.gmail-smtp-in.l.google.com[209.85.233.27]:25: Connection timed out
May 6 03:39:41 dumitru postfix/smtp[15881]: connect to alt1.gmail-smtp-in.l.google.com[2a00:1450:4010:c03::1b]:25: Connection timed out
May 6 03:40:11 dumitru postfix/smtp[15881]: connect to alt2.gmail-smtp-in.l.google.com[142.250.4.26]:25: Connection timed out
May 6 03:40:11 dumitru postfix/smtp[15881]: 675F03FA87: to=<idflorin@gmail.com>, relay=none, delay=150, delays=0.22/0.01/150/0, dsn=4.4.1, status=deferred (connect to alt2.gmail-smtp-in.l.google.com[142.250.4.26]:25: Connection timed out)
May 6 03:41:01 dumitru postfix/anvil[15873]: statistics: max connection rate 1/60s for (submission:109.102.44.68) at May 6 03:37:40
May 6 03:41:01 dumitru postfix/anvil[15873]: statistics: max connection count 1 for (submission:109.102.44.68) at May 6 03:37:40