I still have errors after following the answer
The log is
Apr 23 05:10:52 atlantic postfix/error[30337]: 345C541BDC: to=xxx@xxx.com, relay=none, delay=433026, delays=432875/150/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to aspmx3.googlemail.com[209.85.145.26]:25: Connection timed out)
Apr 23 05:10:52 atlantic postfix/qmgr[30268]: 345C541BDC: from=xxx@xxx.com, status=expired, returned to sender
Apr 23 05:10:52 atlantic postfix/cleanup[30338]: BE6C041389: message-id=20180423091052.BE6C041389@atlantic.localdomain
Apr 23 05:10:52 atlantic postfix/qmgr[30268]: BE6C041389: from=<>, size=5228, nrcpt=1 (queue active)
Apr 23 05:10:52 atlantic postfix/bounce[30332]: 345C541BDC: sender non-delivery notification: BE6C041389
Apr 23 05:10:52 atlantic postfix/qmgr[30268]: 345C541BDC: removed
Apr 23 05:10:52 atlantic postfix/error[30335]: BE6C041389: to=xxx@xxx.com, relay=none, delay=0.02, delays=0.02/0/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to aspmx3.googlemail.com[209.85.145.26]:25: Connection timed out)