Webinar Invites not being received

[pmterp]

Hello,
The 3CX server uses a custom SMTP server for email and all other emails (registration, trunk down, welcome email, etc.) are working.
I've created a webinar and the only option for email (which is pre-selected and grayed out) is Email (legacy, no RSVP) which is fine with me.
However, if I add participants within the 3CX app or if they sign up using the form utilizing the 3CX Webinar WordPress plugin, the confirmation emails are not being received. So far, we have not confirmed a single one has been received. We've tested with email addresses on our own domain as well as Gmail and a couple of others.
How can we troubleshoot this further?

 

[MarcelloV]

Hi @pmterp , you should check you PHP logs for errors. Also check WebMeeting.log on your PBX instance.
If you go to meeting page in PBX console, do you see the participants added to the meeting?

 

[pmterp]

@MarcelloV thanks for the reply. I'll check the logs in a bit but for clarification, the participants are being added successfully whether I add them directly in 3CX or by the WordPress extension. They show up in the list of participants, they just do not receive the email with the join instructions.

 

[MarcelloV]

I understand. In this case, the issue seems at PBX level, PHP logs are clean for sure. Which 3CX version are you using?

 

[pmterp]

I understand. In this case, the issue seems at PBX level, PHP logs are clean for sure. Which 3CX version are you using?

v18u8 (build 939)

 

[MarcelloV]

It's the last one, good. I suggest to put logs in verbose to gather more details.

 

[pmterp]

It's the last one, good. I suggest to put logs in verbose to gather more details.

Will do. Should I be able to change the email option or is that supposed to be the only option?
I'm fine with no RSVP but the fact that banner shows up makes me think there should be other options.

 

[pmterp]

It's the last one, good. I suggest to put logs in verbose to gather more details.

Logs set to verbose (did a full server reboot just to be sure).
I created a new webinar and still only have the one email option.
I added one participant while creating the webinar. (Microsoft 365 email address)
I added a second participant from the 3CX Windows app after the webinar had been created. (Dreamhost hosted email address)
I added a third participant from the WordPress plugin. (Gmail address)
All 3 show up in the webinar's participants list but no confirmation emails were received, same as before.
I've pulled the 3CXWebMeeting.log and see the creation of the meeting. I don't see any entries that are clearly related to the first two participants added. I do see entry for the third, the one done through WordPress. However, I don't see anything in this log related to emails or invites being sent. Do you know what I should be looking for or would that be in a different log?
I did generate a support package in case I need to open a ticket.

I'm curious is anyone else is having this issue on the newest build or if I'm "special"?

 

[pmterp]

One more update. On a different server, I changed the server's email settings to 3CX SMTP server and ran the same test (minus the WordPress plugin) and this time, the email invites were received.
I did pull the 3CXWebMeeting log from that server too and it also doesn't show anything that I can tell is related to the emailing of invites.
So the issue could be that 3CX isn't initiating sending the invites or it could be something with our SMTP server but as previously mentioned, it is working for all other server generated emails.
If I could find a log entry that indicates the email invite being sent, that could help shed some light on where the issue is.

 

[MarcelloV]

WebMeeting email can be slightly different. I would check your SMTP server configuration and logs for more hints. If it works with 3CX SMTP server, it doesn't seem a problem related to our platform.

 

[MarcelloV]

Moreover: if there are no errors related to SMTP in PBX logs (check also 3CXSystemService.log and 3CXManagementConsole.log) it's a good hint that emails are correctly sent to your SMTP server and something unexpected happens there.

 

[pmterp]

Moreover: if there are no errors related to SMTP in PBX logs (check also 3CXSystemService.log and 3CXManagementConsole.log) it's a good hint that emails are correctly sent to your SMTP server and something unexpected happens there.

Thank you, found the SMTP errors in 3CXManagementConsole.log
Check this out:

2023/10/06 11:27:03.335|26656|0054|Warn|MYPHONE: Failed to send mail: MailKit.Net.Smtp.SmtpCommandException: 5.2.254 InvalidRecipientsException; Sender throttled due to continuous invalid recipients errors.; STOREDRV.Submission.Exception:InvalidRecipientsException; Failed to process message due to a permanent exception with message [BeginDiagnosticData]A message can't be sent because it contains no recipients. InvalidRecipientsException: A message can't be sent because it contains no recipients.[EndDiagnosticData] [Hostname=BYAPR16MB2838.namprd16.prod.outlook.com]
   at MailKit.Net.Smtp.SmtpClient.ParseMessageDataResponse(MimeMessage message, SmtpResponse response)
   at MailKit.Net.Smtp.SmtpClient.MessageDataAsync(FormatOptions options, MimeMessage message, Int64 size, CancellationToken cancellationToken, ITransferProgress progress)
   at MailKit.Net.Smtp.SmtpClient.SendAsync(FormatOptions options, MimeMessage message, MailboxAddress sender, IList`1 recipients, CancellationToken cancellationToken, ITransferProgress progress)
   at MailKit.Net.Smtp.SmtpClient.SendAsync(FormatOptions options, MimeMessage message, MailboxAddress sender, IList`1 recipients, CancellationToken cancellationToken, ITransferProgress progress)
   at TcxMail.SmtpMail.SendAsync(TcxMessage message, CancellationToken cancellationToken)
   at TcxMail.SmtpMail.SendAsync(TcxMessage message, CancellationToken cancellationToken)
   at MyPhoneServer.Common.ClientManager.ServerMessageProcessor.SendInviteToParticipant(MeetingObj meeting, IDictionary`2 stat, ParticipantDetails participant, String emailToSend, String mailTemplateParam)

This line: "Failed to process message due to a permanent exception with message [BeginDiagnosticData]A message can't be sent because it contains no recipients." makes it look like no recipient is being included in the sent invite. I'm assuming if that's the case, that would be a 3CX issue.
If you're able, please test using any custom SMTP server and see if it works correctly. I'm going to test with a different SMTP server and see if it makes a difference but if the recipient isn't being included, I think we'll get the same result.

 

[MarcelloV]

Thanks for your feedback on this issue. Would you mind sending the Support Info zip in a private message? Upload it somewhere and share (privately) the url. Please specify the problematic webinar too (any webmeeting access url will do).

 

[pmterp]

Thank you, I've replied to the private message with the support info.
I did just make another discovery. The custom SMTP being used on the server was a Microsoft 365 server, but in 3CX it was setup as Custom SMTP Server and not as Microsoft 365. I've now setup the M365 integration on the 3CX server, switched the email to Microsoft 365 and the invites are now showing up.
Because some of our clients are using services other than M365 or we are not able to setup the M365 integration for them, I'd still like to verify the functionality works when using the custom SMTP server option.

 

[pmterp]

@MarcelloV one last update. I've just tested using a different custom SMTP server and the invites were received successfully. So, the issue seems to be when using a M365 server without using the M365 integration as far as I can tell.

 

[MarcelloV]

Thanks for your help. We'll check this specific configuration and verify if we can reproduce. I'll update the thread the moment we have some news.