I am recieving email but can't send email to like gmail or other services

Hi
I have installed cyberpanel first time on Linode server and did all basic settings.
Now i have created an email account under @domain.com but i can’ send email and please let me know that how to do smpt setting in a classified site. I did the configuration last time on the same classified site for my client when it was on cpanel.

here is the domain: https://adpost.us

here is the mail log:

Sep 4 16:18:05 localhost postfix/qmgr[433592]: E175E2A1F6B: from=adpos1805@localhost.localdomain, size=875, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: EE6AC2A1CCB: from=adpos1805@localhost.localdomain, size=976, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: B143C2A202F: from=adpos1805@localhost.localdomain, size=862, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: F0D562A1ED8: from=adpos1805@localhost.localdomain, size=862, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: 9113C2A1F13: from=adpos1805@localhost.localdomain, size=887, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: 417472A1CC4: from=adpos1805@localhost.localdomain, size=860, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: 4D1BD2A1E42: from=adpos1805@localhost.localdomain, size=853, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: 86C682A1EB3: from=adpos1805@localhost.localdomain, size=849, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: DD6A52A2028: from=adpos1805@localhost.localdomain, size=816, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: 683CA2A202A: from=adpos1805@localhost.localdomain, size=1634, nrcpt=1 (queue active)
Sep 4 16:18:05 localhost postfix/qmgr[433592]: 368E82A1CC7: from=adpos1805@localhost.localdomain, size=866, nrcpt=1 (queue active)
Sep 4 16:18:35 localhost postfix/smtp[435660]: connect to gmail-smtp-in.l.google.com[172.217.194.27]:25: Connection timed out
Sep 4 16:18:35 localhost postfix/smtp[435656]: connect to gmail-smtp-in.l.google.com[2404:6800:4003:c02::1b]:25: Connection timed out
Sep 4 16:18:35 localhost postfix/smtp[435659]: connect to gmail-smtp-in.l.google.com[172.217.194.27]:25: Connection timed out
Sep 4 16:18:35 localhost postfix/smtp[435657]: connect to gmail-smtp-in.l.google.com[2607:f8b0:400e:c0d::1b]:25: Connection timed out
Sep 4 16:18:35 localhost postfix/smtp[435658]: connect to gmail-smtp-in.l.google.com[2404:6800:4003:c01::1b]:25: Connection timed out
Sep 4 16:19:05 localhost postfix/smtp[435660]: connect to gmail-smtp-in.l.google.com[2404:6800:4003:c0f::1a]:25: Connection timed out
Sep 4 16:19:05 localhost postfix/smtp[435659]: connect to gmail-smtp-in.l.google.com[2404:6800:4003:c01::1b]:25: Connection timed out
Sep 4 16:19:05 localhost postfix/smtp[435657]: connect to gmail-smtp-in.l.google.com[172.253.118.26]:25: Connection timed out
Sep 4 16:19:05 localhost postfix/smtp[435656]: connect to gmail-smtp-in.l.google.com[74.125.68.26]:25: Connection timed out
Sep 4 16:19:05 localhost postfix/smtp[435658]: connect to gmail-smtp-in.l.google.com[172.217.194.27]:25: Connection timed out
Sep 4 16:19:35 localhost postfix/smtp[435660]: connect to alt1.gmail-smtp-in.l.google.com[173.194.202.26]:25: Connection timed out
Sep 4 16:19:35 localhost postfix/smtp[435657]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:400e:c00::1b]:25: Connection timed out
Sep 4 16:19:35 localhost postfix/smtp[435659]: connect to alt1.gmail-smtp-in.l.google.com[173.194.202.26]:25: Connection timed out
Sep 4 16:19:35 localhost postfix/smtp[435656]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:400e:c00::1a]:25: Connection timed out
Sep 4 16:19:35 localhost postfix/smtp[435658]: connect to alt1.gmail-smtp-in.l.google.com[142.250.115.27]:25: Connection timed out
Sep 4 16:20:05 localhost postfix/smtp[435657]: connect to alt1.gmail-smtp-in.l.google.com[173.194.202.26]:25: Connection timed out
Sep 4 16:20:05 localhost postfix/smtp[435660]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:400e:c00::1a]:25: Connection timed out
Sep 4 16:20:05 localhost postfix/smtp[435659]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:400e:c00::1a]:25: Connection timed out
Sep 4 16:20:05 localhost postfix/smtp[435656]: connect to alt1.gmail-smtp-in.l.google.com[173.194.202.26]:25: Connection timed out
Sep 4 16:20:05 localhost postfix/smtp[435658]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4023:1004::1a]:25: Connection timed out

Note: it’s my client site and I recommend him cyberpanel because of cpanel cost. So, please help me to resolve this issue.

Thanks

just contact linode to check SMTP port
then check your DNS Configuration
and it will be nice if turn of ipv6 lol
dont forget to set mail.hostname and IN PTR