1
vote
2answers
1k views

What does Diagnostic-Code: SMTP; 573 mean?

I am using sendmail to send mail from my Rails application. But, there seems to be a error happening while sending mails to a specific user domain. The error from /var/mail/* is as follows: Date: ...
3
votes
1answer
899 views

Prevent mail being marked as spam

This is a canonical question about avoiding outgoing mail being classified as spam. I'm wondering how to prevent my emails from my site being marked as spam? I'm using sendmail. I'm trying to ...
0
votes
6answers
684 views

How to ensure mail delivery for our app?

We have a Rails app used for support & help tickets. It sends customers a confirmation email when they submit a request. It also sends an email when we reply to their request. It does not ...