NS_E_DRM_UNABLE_TO_OPEN_PORT: Fix the 0XC00D28AF Error

Cause #1: Windows Firewall is Blocking the Port

This error almost always shows up when Windows Firewall (or a third-party firewall) blocks the port that DRM uses for proximity messages. On most systems, that's UDP port 16018. I've seen this on Windows 10 and 11, especially after a big update that resets firewall rules.

The fix is to allow that port through the firewall. Here's how:

1. Open Windows Defender Firewall by searching in the Start menu.
2. Click Advanced settings on the left.
3. In the left pane, select Inbound Rules.
4. Click New Rule on the right.
5. Choose Port, then click Next.
6. Select UDP and type 16018 in the Specific local ports field.
7. Click Next, select Allow the connection, then Next.
8. Check all profiles (Domain, Private, Public) and click Next.
9. Give it a name like "DRM Proximity" and hit Finish.

Now repeat those steps for Outbound Rules too. I know it's tedious, but it covers both directions. Once done, restart your media app and the error should be gone.

If you're using a third-party firewall like Norton or McAfee, you'll need to add the same port rule in their interface. The steps vary, but look for "port" or "application" rules.

Cause #2: Windows Media Player DRM Service Not Running

Another common culprit is the Windows Media Player Network Sharing Service — it handles DRM stuff, and if it's disabled, you'll get this exact error. I've seen this happen after a clean install or when someone disabled services to 'speed up' Windows.

Here's how to check and fix it:

1. Press Win + R, type services.msc, and hit Enter.
2. Scroll down to Windows Media Player Network Sharing Service.
3. Double-click it. Set Startup type to Automatic (or at least Manual).
4. If the service status is not Running, click Start.
5. Click OK and close the window.

Sometimes the service fails to start with a permissions issue. In that case, open Command Prompt as Administrator and run:

sc config WMPNetworkSvc start= auto
net start WMPNetworkSvc

This forces it to start. If you get an error, check the Event Viewer for more details, but usually this does the trick.

Cause #3: DRM Registry Key Is Corrupt or Missing

This one's less common but real. The DRM subsystem stores its state in the registry, and if a key gets corrupted — say, after a bad uninstall of some media software — the port won't open. The fix is to delete the DRM folder and let Windows rebuild it.

Warning: This will reset your DRM licenses for any old content. You might have to re-download or re-authorize stuff. I'd only do this if the first two fixes didn't work.

Here's the safe way to do it:

1. Close all media players, especially Windows Media Player.
2. Press Win + R, type regedit, and hit Enter.
3. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Media DRM.
4. Right-click the Windows Media DRM key and choose Export to back it up somewhere.
5. Then delete that key.
6. Restart your PC.

Windows will recreate the key on next boot. Then try playing something DRM-protected again. I've seen this fix work when nothing else did, but be prepared to reauthorize your media library.

Quick Reference Table

Start with the firewall — it's the most common. If that doesn't get you there, try the service. Only mess with the registry if you're comfortable and the other fixes fail. You'll get this sorted.