I can receive emails but I cannot send emails to other people.

Please help me, I am also not getting forwarded emails to my Gmail mailbox from my domain's email account. I have setup email forwarding.

Below is the log:

Apr 25 17:57:22 cloud.XXX.com postfix/smtp[17350]: connect to gmail-smtp-in.l.google.com[74.125.195.26]:25: Connection timed out
Apr 25 17:57:22 cloud.XXX.com postfix/smtp[17350]: connect to gmail-smtp-in.l.google.com[2607:f8b0:400e:c08::1b]:25: Network is unreachable
Apr 25 17:57:52 cloud.XXX.com postfix/smtp[17349]: connect to alt1.gmail-smtp-in.l.google.com[142.250.115.27]:25: Connection timed out
Apr 25 17:57:52 cloud.XXX.com postfix/smtp[17349]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4003:c15::1a]:25: Network is unreachable
Apr 25 17:57:52 cloud.XXX postfix/smtp[17350]: connect to alt1.gmail-smtp-in.l.google.com[142.250.115.27]:25: Connection timed out
Apr 25 17:57:52 cloud.XXX.com postfix/smtp[17350]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4003:c15::1a]:25: Network is unreachable
Apr 25 17:58:22 cloud.XXX.com postfix/smtp[17349]: connect to alt2.gmail-smtp-in.l.google.com[142.250.128.26]:25: Connection timed out
Apr 25 17:58:22 cloud.XXX.com postfix/smtp[17350]: connect to alt2.gmail-smtp-in.l.google.com[142.250.128.26]:25: Connection timed out

25: Connection timed out
it seems smtp port 25 is blocked.

Check with your hosting provider, if this is a new account it may be blocked on purpose and you have to actually contact them to open the ports. At least that was the case in my situation with Linode.