Outgoing messages not be received by intended recipient

[arrowheadsolutionsllc]

We've become aware of a problem regarding our sent mail. I'm not sure how widespread it is since there is no read-receipt option in the email and many people do not follow up with us to let us know they didn't get a message. But we've learned that our messages are not being received by non-Zimbra users.

The message shows up in our sent box and we do not get an "undeliverable" message or any other message that would clue us into the problem. We only know about it if we message a client or call them to discuss the email and they say they never got it. This has happened to a variety of intended recipients and I'm not sure how long it has been going on. Some messages have attachments and some do not. I use Google Chrome, but my business partner uses Explorer.

Any solutions or ideas to ensure messages are being sent? Is there a way to get a "read receipt" in Zimbra mail? This has caused us to look like slackers with clients I'm afraid since we do not look responsive. And with all our traffic, I don't want to call every single recipient to see if they got a message. We are using 5.0.19.

Thanks

[phoenix]

Look in the log files for details of messages that are sent via the ZCS server, you'll see connection attempts to the recipient mail server. I'll also move this thread to the correct forum as it doesn't appear to be a Zimbra Desktop question (which is where you posted it).

[Labsy]

Check also:
- your reverse PTR for Zimbra server's public IP address, which should resolve to main zimbra FQDN or a sub-domain
- Once I had problems with Zimbra' MTA not being authorised, and this command solved the problem:

sudo /opt/zimbra/bin/zmprov –m –l yourZimbra.server.com zimbraMtaAuthHost yourZimbra.server.com

- did you try sending out to your Gmail or Yahoo mail account? Look at received mail headers, spam score, ham or spam etc. to get some clue
- check your Zimbra IP for blacklists. If you are on at least 1 blacklist (except blackscatter, which is not relevant), you might get random delivery rate, depending on how tight recipient's security is.
- do you send mail out directly or smarthost via ISP's SMTP server? If you send out directly, your ISP might have changed security policy and begun blocking port 25 for any mail server, except their own. This was the case with few of our customers.

[arrowheadsolutionsllc]

Thank you for the help-however, you'll have to excuse me. Our business is comprised of two people, and accountant and contracts manager. We use Zimbra because it came with our website being hosted by Homestead.
Therefore, I am a complete neophyte with trying to trouble shoot this.

How do I check log files? Labsy - the only question I can answer is that I did try to send to Gmail and Yahoo and it works. But I did these only as tests and our issue seems to be happening randomly.

Any guidance on how I can figure this out without going back to school?

Thanks!

[Labsy]

Hi,
I sent you a private massage to diagnose your mail server 1-to-1. I'll post results here as I dig something useful of it.

In the meantime you can play with diagostic tools yourself, for example, you can test your mail for proper configuration and blacklists at MX Lookup Tool - Check your DNS MX Records online - MxToolbox

[arrowheadsolutionsllc]

Thank you - hopefully the diagnosis provides something useful. Thank you for the diagnostic tools link, I'll play with it today and see what I can learn.