Suddenly got several reports of OLD missed call notifications showing up this past weekend

[RDWild]

We just had several users on the same 3CX system report getting missed call notification emails for calls that happened back in August and September. Can anyone tell me why this might be happening?

 

[SteveITS]

Had they been logged out and logged in to the web client again? IIRC I’ve seen something like that as it processes the old notifications…

 

[KyriacosS_3CX]

Or could be email that were stuck in limbo somewhere - your logs should provide some clues.

 

[RDWild]

I don't think they were logged out, they continued to get notifications, on time, for other missed calls.

I don't see how the message could have been stuck either. We use M365 as a mail server, and message trace shows it being received on Sunday and delivered to the users' mailboxes seconds later.

 

[Alphabetic]

OS spec?
Anything else running on it?

 

[RDWild]

It's hosted by 3CX.

 

[SteveITS]

Oh I missed that it was emails. I've seen the popup notifications appear. It's been a while so I don't quite remember why, but it sorta made sense at the time...opening a client, after a long time, or something like that. Couldn't reproduce in some quick testing. So never mind.

Random thoughts...what email system? M365/Exchange discards duplicate emails (via Message ID AFAIK) but I'm not sure how far back it looks. Is a third party spam filter in use in front of it? And what is 3CX using to send messages?

 

[RDWild]

3CX is using a M365 mailbox. Yes, we have Inky as a spam filter, but it actually is on the backend of M365, it looks and tags emails as they arrive in the user's mailbox.

 

[SteveITS]

Any chance the server had just restarted?

If you download the support package, look at logs/3cxSystemService.log for "mail" e.g.:
2025/08/12 10:09:24.995|0044|Erro| [_3CX.Mail.MailSenderService] Send mail failed: 4.3.2 Temporary server error. Please try again later ATTR1 [SJ1PEPF00002314.namprd03.prod.outlook.com 2025-08-12T15:09:24.705Z 08DDD91FCC8F9653]