Specific Mailboxes in Unity Conn Unable to Receive Certain Voicemails

[UCAdmin405]

I've got a weird issue with my CUC cluster (v15su2). I've tracked it down to about 12 user mailboxes (that I know of) out of about 2500. We utilize UMS which is synchronized to our google environment. All the tests and troubleshooting around UMS with google are successful. I know its working because these 12 mailboxes which are Active directory user integrated will successfully receive voicemails left by external callers and internally callers from phones that are shared and have no active directory user assigned to them. The 12 users will successfully get the voicemail delivered to their email inboxes from these callers. However, anyone calling from a active directory associated user's phone and trying to leave a voicemail to one these 12 mailboxes will get a bounce back email stating that a "Delivery Status Notification (Failure) Message could not be delivered to the following recipient(s): exampleuser@examplecompany.com". I pulled logs I thought might have the answer but didn't see an obvious cause or error. Reconfigured the micro traces and and enabled all levels. Duplicated the issue and pulled new logs and still no direction but I now see the a failure message but it's just the same message as the email bounce back with no indicative information as to the caue. I'm in the process of engaging TAC but I'm hoping maybe someone here has had a similar experience and can share their resolution quicker than a TAC case can help diagnose. It worth mentioning the cluster/database is healthy and I even gave it the old "turn it off and back on again" yesterday but the issue still persists.

Anyone ever had an issue like this?

[Brad Magnani]

Hi @UCAdmin405,

A high level flow of message delivery is that it'll get recorded, delivered locally to the DB, then synced out to any UM integration (O365, GSuite) or notification devices (SMTP, Pager, etc.).  Based on what you're describing it likely isn't related to the GSuite integration and the problem is happening prior to that when it's trying to deliver messages locally.  Set these micro traces and reproduce the issue and I can take a quick look if you want to DM me the logs.  

Macros:
Call Flow
Call Control
Conversation Traces
Message Tracking Traces
Traces for other Notification Problems

Micros:
MTA - all levels

Gather from RTMT:
Connection Conversation Manager
Connection Message Transfer Agent
Connection Notifier

Include calling # and alias
Called # and alias
Timestamp of the message being left

Brad

[UCAdmin405]

Hey, Brad, you are correct. I did some more testing after posting and determined that the mailbox itself is not even getting the voicemail. Still unsure why it's not accepting it but let me get everything configured and get the logs pulled. But I agree, it has nothing to do with my Gsuite integration as I first thought. I'll reach out with the logs in a bit. Thanks for your reply!

[UCAdmin405 · Accepted solution]

Well turns out I've misunderstood the difference between "use system settings" and "system maximum" for mailbox quotas for a decade, I'm embarrassed to say. The confused on this issue has stemmed from a checkbox I've never dealt with before; "Full Mailbox Check for Outside Caller Messages". Long story short the affected users mailboxes were full but the check box I just mentioned was not checked which allowed "unknown" callers (PSTN calls and phones with no user assigned to them) to still leave these users voicemails. This is what was causing only "certain" voicemails to be successfully left on the mailbox. I tweaked these settings and cleaned out the mailboxes and everything is back to normal. Hopefully my ignorance will save someone in the future this trouble. 

[Maren Mahoney]

I taught for a bunch of years and always pointed out that checkbox to new administrators so it was in their brain for later. It bites folks in the butt a lot.

I'm probably not telling you anything you don't already know, but message aging policy can help keep mailboxes from getting full in the first place.

Thanks for sharing your solution for folks reading this thread later!

Maren

[UCAdmin405]

Yep, those have been updated as well, but thanks for the comment though! Another great thing to double check for any admins.