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Handset Notifications For Microsoft Teams Voicemail Not Working 

John Marrett, Managed Network Service Technical Lead
February 14, 2024

Our client contacted us when they noticed Microsoft Teams voicemail was not working correctly on their handsets. The problem they identified was not receiving notifications for voicemail. They believed Teams voicemail notifications had worked in the past; they definitely weren’t working when they contacted us.   

I love sharing interesting stories from our technical team that can help the Microsoft user community. Bhanu, a senior member of our managed service team who’s been working at ZIRO for three years, handled this case. His colleagues supported him through the long weeks he spent struggling to solve this problem for our client.  

At first, we suspected common area phones using a Microsoft Teams Shared Device might not correctly support Microsoft Teams voicemail. Microsoft has published conflicting documentation on the subject, stating that voicemail isn’t supported in some documents and that it could be enabled using advanced calling features in others. Our client was experiencing problems with Teams voicemail not working on a SIP Device and not a Microsoft Teams phone. The device type made us wonder if the common area phone might be part of the problem.  

We investigated with Poly, the phone manufacturer, and Microsoft but received only cursory responses. In our support tickets, the Microsoft team didn’t provide a clear answer on feature support for voicemail instead giving conflicting and unclear answers that didn’t help us solve the problem.   

Poly support stated Teams voicemail notifications should work and were able to confirm the functionality worked properly in their lab. They couldn’t test with a Microsoft Teams Shared Device license and could offer no meaningful guidance or explanation for why it did not work for the client. Both vendors pointed the finger at the other and didn’t help us or our client.  

Bhanu, our support tech, continued investigating the problem with Teams voicemail not working on the device and discovered that the issue was more widespread than we initially understood. The voicemail not working problem wasn’t limited to Poly phones, the Teams client didn’t show voicemail properly in our client’s tenant. The Microsoft Remote Connectivity Analyzer reported, “No voicemail messages were found in the Outlook Voicemail Search folder.” When Bhanu viewed the folder using Outlook, the messages could be seen and listened to without any issues.  

The Microsoft support team continued to ask us to repeat basic tests. They offered no suggestions on how to solve the problem. Poly closed the case as non-reproducible. 

Finally, something clicked while Bhanu looked at the voicemail folder as a test user. He noticed that there was a legal disclaimer on the voicemail message. The client investigated and realized that the problem started following the addition of an organization-wide signature policy.   

Often the hardest part of solving a problem is understanding the root cause, once we determined that the signature was preventing teams from identifying the voicemail messages it was easy to add a rule to exclude messages containing an attachment named “audio.mp3”. With the disclaimers removed, Microsoft Teams and the phone’s voicemail started working again. Message parsing logic in the Teams infrastructure could not handle the addition of our client’s signature to the email containing the voicemail messages. That is why voicemail was not working.  

Here’s what our client said about their experience in their CSAT survey response:  

“This issue was very difficult to sort out. Bhanu did an excellent job. He stayed persistent week after week after week until we found a resolution. Very happy with the results.”  

Sharing unique experiences like this with the Microsoft Teams and ZIRO communities is a pleasure. We found other people experiencing similar issues when we discussed the issue on the Microsoft forums.  

As organizations transition from on-premises phone system solutions to cloud-hosted solutions, consumers of these services expect that their cloud service provider will handle everything. Cloud provider support is for the core service, but the devil is in the details. When something important to your organization slips through the cracks, it can be challenging to resolve it without 3rd party support.  

Most organizations need a resource beyond the cloud service provider to lean on for day-to-day support. ZIRO is a go-to resource for Microsoft Teams phone system customers. If you need day two support for Microsoft Teams, we should talk. We love solving challenging problems. 

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