Hi @Intune_Support_Team ,

I have recently come across with an Issue.

Issue: Call Dropout, Network freeze on AV Calls for Apps / Platforms

Description: I have noticed this issue on only MacOS Devices enrolled on Intune; that are later updated to MacOS15 Sequioa using Intune policy Mac Update policy + MS Defender for Endpoint Enrolled, with MS Defender Network Filter added to the list, hangs / freezes AV calls for 2-3 seconds like a network glitch on Slack Huddles. 

This also happens on 3CX Telephone app in bit different way as 3CX agent’s audio is not heard by far-end Customer.

Both of these only happens on Device upgraded to MacOS 15 + Defender + Network Filter with just Slack and 3CX. Google Meet, Zoom, Teams works well.

NOTE : Compared to a Device which is not on Intune /Defender with MacOS 15 Slack Huddle and 3CX is a Charm.

I also tried initially to look into Apple MacOS bugs, didnt find much, then raised a request to Slack Support, In Response I got this 

Hi there Swapnil,

Thanks for contacting Slack support. What is happening here is that users are losing media connectivity to the huddles server, causing them to drop and then be reconnected. This can happen for a number of reasons, but if you’ve recently updated to macOS 15 Sequoia, there is a macOS networking bug which is highly likely to be the cause in this case (https://support.apple.com/en-au/102281).

The issue is as follows:
Overall the connection may be completely fine.
Suddenly the media connection to the huddles server stops completely (even if the rest of the internet connection is fine).
After the huddles server detects a period of no data being sent/received, it forces the client to reconnect to the huddle.
This can help for some time but it may eventually repeat again through each huddle.

Unfortunately in each case we cannot help explain the exact underlying cause is as it occurs on the end of each users network environment. In your case however, if users are experiencing the issue after upgrading to macOS 15, the aforementioned networking bug is the most likely cause.

Normally the causes of these kinds of issues are as follows:
Firewall or other network configuration closing websockets media connections.
The macOS Sequoia bug causes this specific kind of problem.
Overzealous modem/router throttling media connections.
ISP throttling media connections.

On the another response they also mentioned about something is probably not right with MS Defender Network Filter blocking out traffic for AWS Chime Server.

Hi Swapnil,

Thanks for your reply. Because there are so many variables we aren’t going to be tracking this on our side.

One thing I would say is that you should just be sure that there are no third party dependencies in your macOS environment which might be in need of an update. I’ll give you a random example:
Organisations using the Zscaler client connector would have encountered a variation of this issue (https://help.zscaler.com/client-connector/firewall-posture-check-failure-macos-sequoia).
The macOS updates alone would not have addressed it, Zscaler needed to issue an update to their client connector software.
Until users were running the Zscaler client with the relevant fix, no amount of system updates would have prevented them from running into the compatibility issue.

So all I am saying is that you should be keeping an eye out for updates to both macOS and any relevant 3rd party dependencies – it’s possible you will need to take manual action in some way first.

The public facing macOS updates tend to be quite vague, so it is probably best to start with MS Defender and any other relevant 3rd party configurations before waiting on a macOS update to ultimately fix the issue. You may also prefer to pre-emptively seek confirmation from their respective support services so you know exactly what your next steps are.

I hope this gives you a better idea on how to approach the issue and plan for updates Swapnil, and apologies I couldn’t provide more guidance.

After reading about this I tried to dig little more and understood, 3CX is also using AWS Chime A/V Servers.

My users are stuck and losing their Slack Huddles which is day to day quick AV.

Any insightful info on this one will be helpful.

Thanks

Swapnil

email address removed for privacy reasons

​Hi @Intune_Support_Team ,I have recently come across with an Issue. Issue: Call Dropout, Network freeze on AV Calls for Apps / Platforms Description: I have noticed this issue on only MacOS Devices enrolled on Intune; that are later updated to MacOS15 Sequioa using Intune policy Mac Update policy + MS Defender for Endpoint Enrolled, with MS Defender Network Filter added to the list, hangs / freezes AV calls for 2-3 seconds like a network glitch on Slack Huddles. This also happens on 3CX Telephone app in bit different way as 3CX agent’s audio is not heard by far-end Customer.Both of these only happens on Device upgraded to MacOS 15 + Defender + Network Filter with just Slack and 3CX. Google Meet, Zoom, Teams works well.NOTE : Compared to a Device which is not on Intune /Defender with MacOS 15 Slack Huddle and 3CX is a Charm. I also tried initially to look into Apple MacOS bugs, didnt find much, then raised a request to Slack Support, In Response I got this  Hi there Swapnil,Thanks for contacting Slack support. What is happening here is that users are losing media connectivity to the huddles server, causing them to drop and then be reconnected. This can happen for a number of reasons, but if you’ve recently updated to macOS 15 Sequoia, there is a macOS networking bug which is highly likely to be the cause in this case (https://support.apple.com/en-au/102281).The issue is as follows:Overall the connection may be completely fine.Suddenly the media connection to the huddles server stops completely (even if the rest of the internet connection is fine).After the huddles server detects a period of no data being sent/received, it forces the client to reconnect to the huddle.This can help for some time but it may eventually repeat again through each huddle.Unfortunately in each case we cannot help explain the exact underlying cause is as it occurs on the end of each users network environment. In your case however, if users are experiencing the issue after upgrading to macOS 15, the aforementioned networking bug is the most likely cause.Normally the causes of these kinds of issues are as follows:Firewall or other network configuration closing websockets media connections.The macOS Sequoia bug causes this specific kind of problem.Overzealous modem/router throttling media connections.ISP throttling media connections.On the another response they also mentioned about something is probably not right with MS Defender Network Filter blocking out traffic for AWS Chime Server.Hi Swapnil,Thanks for your reply. Because there are so many variables we aren’t going to be tracking this on our side.One thing I would say is that you should just be sure that there are no third party dependencies in your macOS environment which might be in need of an update. I’ll give you a random example:Organisations using the Zscaler client connector would have encountered a variation of this issue (https://help.zscaler.com/client-connector/firewall-posture-check-failure-macos-sequoia).The macOS updates alone would not have addressed it, Zscaler needed to issue an update to their client connector software.Until users were running the Zscaler client with the relevant fix, no amount of system updates would have prevented them from running into the compatibility issue.So all I am saying is that you should be keeping an eye out for updates to both macOS and any relevant 3rd party dependencies – it’s possible you will need to take manual action in some way first. The public facing macOS updates tend to be quite vague, so it is probably best to start with MS Defender and any other relevant 3rd party configurations before waiting on a macOS update to ultimately fix the issue. You may also prefer to pre-emptively seek confirmation from their respective support services so you know exactly what your next steps are.I hope this gives you a better idea on how to approach the issue and plan for updates Swapnil, and apologies I couldn’t provide more guidance. After reading about this I tried to dig little more and understood, 3CX is also using AWS Chime A/V Servers. My users are stuck and losing their Slack Huddles which is day to day quick AV. Any insightful info on this one will be helpful. ThanksSwapnilemail address removed for privacy reasons  Read More

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