I installed Posifx on Ubuntu 18.4 LT on an amazon EC2 box. After installation and configuration, I was able to send out two emails to my hotmail and another email account. I do received them. However, I can not send any email any more. I check the /var/log/mail.log. It shows the "connection timed out" Error on these sending attempt.

I am confused why I was able to send but later can not. One thing I am not sure, when configuring the /etc/hosts, I did not use a real FQDN, I just give something like hostname.xxx.com because I can not find FQDN on my amazon EC2 box. Does that cause the problem.

I need to send email out when my application status is changed. Does anyone have experience on sending email from Amazon EC2 box?

Thank you


You need to sign up and configure server to use a SMTP relay service.

Example: https://www.smtp2go.com/

  • I tried gmail relay. It works most time. But sometime I got "connect to smtp.gmail.com[2607:f8b0:400e:c08::6c]:587: Network is unreachable". Do you know why? – Ming Wu Oct 11 '19 at 14:55
  • Does it always have an IPv6 address? – Hannel Oct 11 '19 at 18:56

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