Not Receiving Voicemail Emails

[TagleRock]

Hello. We are not receiving voicemail emails. I've tried three different email addresses, two of them are gmail, one is on an Exchange server and none come through. There are no logs on spam filters or anywhere else, seems like the emails never reach their destination. Might have something to do with 3CX bounce list, but its hard to believe three emails are on there. Unless 3CX's bounce list blocks the PBX from sending out, and not individual recipients.

PBX Info below -
On-Premise
Installed on Debian
Version: 18.0 Update 9 (Build 20)

 

[Charles_3CX]

Which SMTP server are you using? Does the TEST succeed when used under the management console > settings > Email section?

 

[TagleRock]

Using the 3CX SMTP server, the test succeeds and the test email is received when I send a test. Welcome emails also come through.

 

[TagleRock]

You know what its probably not a blocklist since the welcome and test emails come through. Unless those are handled differently.

 

[Charles_3CX]

They are handled in the same way. Check that the vmail option is set to send a vmail via email, and advise to set them to send an attachment via email and not delete and check that when leaving a vmail, they can be seen under the extension web client voicemail tab.

 

[TagleRock]

Yes its set to send vmail as attachment. It had been working for a few years up until recently. The voicemails can be seen in the web client. One thing that is odd is that I set a custom SMTP server and I got one voicemail email that was left 20 minutes ago at the time the email was received. Not sure if that was a fluke, or if it staggers resend attempts.

 

[Charles_3CX]

There is a feature that retries to send emails if it initially fails every 15 minutes for 72 hours.

 

[TagleRock]

Had my hopes up I had found a work around, but it was just that one email that came through. No others have come through, and I've left about three test voicemails since I changed the SMTP server. Test email comes through just fine, so does welcome email, voicemails don't. Going to try a reboot after 5 and see if that fixes it.

 

[TagleRock]

Sorry for the late reply. Was doing some more testing on this and we are now getting more consistent results. All emails when sent to this user's email address from 3cx when using the 3cx smtp servers fail, this includes welcome and voicemail emails. When I switch it to our email server and relay them through there they work just fine, welcome and voicemail come through. Seems that no emails to this user are going through. This person is the only one that uses voicemail to email or any of the email functions of the phone system but we are running a couple of other tests and I will report back.

 

[TagleRock]

I tested with other users and the email comes through, its only this user when 3CX is using 3CX smtp servers that doesn't get emails. If I switch to our email server and have it relay through there it works. I'm back to wondering if this user's email is on some kind of block list on 3cx's side.

 

[SweetAction]

I tested with other users and the email comes through, its only this user when 3CX is using 3CX smtp servers that doesn't get emails. If I switch to our email server and have it relay through there it works. I'm back to wondering if this user's email is on some kind of block list on 3cx's side.

If you bounce a message through 3CX SMTP, it will block the address for 7 days.

So yes, if 3CX SMTP tries to email your client and the mail server is down for maintenance right then, 7 day block.

Use your own SMTP is what we almost always recommend.

 

[TagleRock]

If you bounce a message through 3CX SMTP, it will block the address for 7 days.

So yes, if 3CX SMTP tries to email your client and the mail server is down for maintenance right then, 7 day block.

Use your own SMTP is what we almost always recommend.

Thanks for the info, we switched it to our server late Friday and have had no issues since. Bit of a strange security policy on 3CX's side to block the address for a week for one bounce, but oh well, its working so that's what I care about lol.

 

[TheodorosG_3CX]

The email will be bounced is there is an error received from your SMTP side.
This cannot be changed however you can always use your own custom SMTP if you want.

 

[SweetAction]

Thanks for the info, we switched it to our server late Friday and have had no issues since. Bit of a strange security policy on 3CX's side to block the address for a week for one bounce, but oh well, its working so that's what I care about lol.

Out of sheer curiosity, how would you configure it (3CX's mail server)? Just let mails keep bouncing?

 

[TagleRock]

Out of sheer curiosity, how would you configure it (3CX's mail server)? Just let mails keep bouncing?

If you mean the settings under mail in 3CX I just had it set to the 3CX SMTP server. User extension had the user's email on it.

 

[SweetAction]

If you mean the settings under mail in 3CX I just had it set to the 3CX SMTP server. User extension had the user's email on it.

No, I meant in reply to this:

Bit of a strange security policy on 3CX's side to block the address for a week for one bounce

If it's strange, how would you do it? Just let mails bounce? Something else?

 

[TagleRock]

No, I meant in reply to this:

If it's strange, how would you do it? Just let mails bounce? Something else?

Strange part to me is the length of the block on the first block. I wouldn't block it on the first bounce, I would do a more reputation based block. So something like

1st bounce - Log it
2nd bounce - Hour long block
3rd bounce - 8 Hour long block
4th bounce - Week long block
5th bounce - Permablock until manually unlisted.

Would also create an interface to check if the address is actually listed and provide a method for self service de-listing (similar to an IP blacklist). First one or two might be automated, others would require review by staff to ensure there are no current bounce backs or things that might cause undue stress on 3CX's SMTP servers.