[Bug] - Microsoft Cast to a Microsoft Wireless Display Adapters failure

[MPeg76]

Baseline Info:

• OS: Windows 11 24H2 / 25H2
• OIB Version: 3.7

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Describe the bug

When attempting to connect via Microsoft Cast to a Microsoft Wireless Display Adapter (or any Miracast-compatible display/TV), the target device is visible in the cast menu and the TV shows "Connecting..." — but the connection never completes and eventually times out.

This affects any Miracast-based solution (smart TVs, conference room displays, Microsoft Wireless Display Adapter, etc.). The issue does not occur on unmanaged devices.

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Root Cause (suspected)

Miracast relies on dynamically created inbound Windows Firewall rules that are added locally when wireless display is initiated. When local firewall rule merging is blocked by policy, those rules never apply and the connection is silently dropped by Windows Firewall.

When connecting via Miracast, Windows uses a direct Wi-Fi (Wi-Fi Direct / P2P) connection to the display, which is classified under the Public firewall profile. The following two settings in Win - OIB - ES - Windows Firewall - D - Firewall Configuration - v3.1 are the likely culprits:

Setting	Profile	Value	Effect
Allow Local Firewall Rule Merge	Public	False / No	Blocks dynamically created Miracast inbound rules
Shielded (Shielded Mode)	Public	True / Yes	Drops all inbound connections on the Public profile

Is anyone else experiencing this?

[itkama]

I experienced that problem way before ever hearing of OIB. You can easily just create your own rule in Intune:

These are my settings that solved it for me. Haven't checked it in a while, but also heard no complaints from users.

Maybe it would be a good idea to add this as a baseline rule? I would assume most people in an office setting would want Miracast to work for meetings and such?

[ak47uk]

I had this issue a long time ago and also resolved using an almost identical rule to above (network type and interface type not set which should be to allow 'all'), I find it can be flaky still. When I saw this post I tried to connect to a TV and it failed with "couldn't connect", I tried a few more times and one of those times it worked, I disconnected and now it won't work again.
I have experienced the same on other smart TVs. Potentially related to inter-VLAN rules, my IoT VLAN is blocked from accessing other VLANs but related established/traffic is allowed and my private VLAN can connect to my IoT VLAN.