I am using the following guide: https://www.linode.com/docs/email/postfix/email-with-postfix-dovecot-and-mysql/
I followed everything, and it's a very good guide, but there is no mention of whether a user, e.g, /home/jack, needs any mailbox configuration. Do I need to do anything, such as "touch /home/jack/mbox" or add jack to a mail group, etc? Other than that, it seems like it's working for outgoing mail, but when I sent an email (via Gmail or by Gmail Smarthost configuraiton on my home laptop, I get the following error:
The recipient server did not accept our requests to connect. Learn more at https://support.google.com/mail/answer/7720
[lifepngcare.org. 2400:8900::f03c:91ff:fedb:8c14: timed out]
[lifepngcare.org. 184.108.40.206: generic::failed_precondition: connect error (111): Connection refused]
[mail.lifepngcare.org. 2400:8900::f03c:91ff:fedb:8c14: timed out]
[mail.lifepngcare.org. 220.127.116.11: generic::failed_precondition: connect error (111): Connection refused]
Any ideas given the error message? Thanks.
This error message is one that has been perplexing quite a few people, but I think I may have found an answer. The following error is a bounce message that is specific to Gmail and is appearing either due to an SPF failure or because Gmail's sending IP was blacklisted. For further explanation of this error message I suggest reviewing this site, How to handle this strange Gmail bounce.
Whether it's the SPF record or a blacklisting of the Gmail IP, the remote server is rejecting the email which is why you're getting this message. If the SPF record is the issue, you can verify this by checking your DNS Manager. I'd recommend that you review this site that has many good directions on How to create an SPF TXT record?
You will want to ensure that SPF is set up correctly for the domain which means configuring the DNS to allow email to be sent by Gmail servers. For specific Google directions on how to add an SPF TXT record, you can review this site, Help prevent email spoofing with SPF.
If a blacklisted Gmail IP is the issue, then there is very little you can do and this vague message was sent simply because Google doesn't want the end user to know that they have a blacklisted mailer IP. Hopefully, Google will take measures to get that IP removed from whichever blacklist(s) it is on, but that could take some time. If a blacklisted Gmail IP is the issue, then you should look into other mail clients. Good Luck!