iRedMail/cubemail not sending to certain domains.

So, I set up an iRedMail, Postfix SMTP, Dovecot IMAP, Nginx, MariaDB, Amavised-new, SpamAssassin, ClamAV, Roundcube, and iRedAPD Postfix policy server for greylisting (which I removed). All on Ubuntu 18.04 server.

Everything works fine when sending out through roundcube to emails such as gmail, etc – though it detects it as spam, and it receives mail fine as well to gmail.

The main problem is it will not deliver mail to other emails of friends on other domains or receive it ( It returns the following error when sending out from cubemail: host[ip.add.ress] said: 550-Verification failed for 550-No Such User Here 550 Sender verify failed (in reply to RCPT TO command)

My friend receives the following error when trying to send me an email to the mailserver: No Such User Here

Reporting-MTA: dns; Action: failed Final-Recipient: rfc822; Status: 5.0.0 is the email I’m sending from to and it doesn’t go through, and vise versa, even though I know the email exists. It also will not send to forwards he has that point to his account.

/var/log/mail.log displays the same error and is of no help.

Here is how my machine and his machine are configured just for clarity. MX records point to another ip outside of the server its domain is hosted on. There are, however, no mx records on as it doesn’t have domains pointing to it via DNS servers to handle it for hosting sites, etc. is by itself at its webhosting company and has many forwarded aliases to the friend account, which are reached through other emails, just not any from, and he cannot send any to

All I’m trying to do is have my mail for a certain domain whose website is hosted on a different server, to handle its mail on a different server, thus leaving its web address alone, etc. I seem to be missing something that is not allowing other domains to recognize it, yet gmail has no problems.

What could be the problem here? Any help is appreciated.

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Hi @kelloggChrisp,

Unfortunately, even if you change MX records and Nameservers, the same issue will appear. The only way to fix this is by turning off the local delivery, at least that I know of.

HI @kelloggChrisp,

Usually, these errors are generated when you have the same domains on one host. host[ip.add.ress] said: 550-Verification
failed for 550-No Such User Here 550 Sender
verify failed (in reply to RCPT TO command)

Basically, if you have the domain on the same droplet/server, mail servers try to send the e-mails locally first. Is that the case here? Do you have any trance of the domain you are trying to send your friend to on the same system?

Regards, KFSys