That proxy error won't go away?
I know this error is infuriating — you're trying to open a video in Windows Media Player or a UWP app like Mail, and boom: NS_E_CANNOT_CONNECT_TO_PROXY (0xC00D2EEE). The app tells you it can't reach the proxy server, but you don't even use a proxy. This tripped me up the first time too, back when I managed a help desk for a mid-sized accounting firm. The culprit is almost always a corrupted Internet Explorer proxy setting that Windows apps inherit.
The fix: nuke the proxy settings
Skip the DNS flush, skip the Winsock reset, skip reinstalling Windows Media Player — none of that touches the proxy config. Here's what works:
- Press Windows + R, type
inetcpl.cpl, hit Enter. - Go to the Connections tab, click LAN settings.
- Uncheck Use a proxy server for your LAN.
- Also uncheck Automatically detect settings (this one's sneaky — it can force a proxy auto-discovery even if the manual proxy box is unchecked).
- Click OK twice, restart the app that threw the error.
That's it for 90% of cases. But if the error persists, you've got a deeper corruption.
When the UI fix isn't enough
Sometimes the registry holds a zombie proxy entry. Open Command Prompt as admin and run:
reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /v ProxyServer /f
reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /v ProxyEnable /f
reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /v AutoConfigURL /fThen reboot. This bites people who used a VPN or proxy switcher that didn't clean up after itself. I once saw a Cisco AnyConnect client leave a dead AutoConfigURL pointing to a PAC file on a server that had been decommissioned.
Why this fix works
Windows apps — especially older ones like Media Player and many UWP apps — use the Internet Explorer proxy stack under the hood. They don't care about your Firefox or Chrome settings. When the IE proxy settings say "use a proxy at 192.168.1.100:8080" and that machine is off, the app times out with 0xC00D2EEE. Disabling the proxy tells the app to connect directly. The registry deletion ensures no leftover junk overrides the UI change.
Less common variations of the issue
Three scenarios I've seen where the basic fix needs a tweak:
- Corporate proxy with authentication: If you actually do use a proxy (like at work), the error means the proxy server is rejecting your credentials. Go to LAN settings, click Advanced, and make sure exceptions list
<local>or specific internal IPs. Then check that your IE credentials are current — typerundll32.exe keymgr.dll,KRShowKeyMgrand clean out stale stored credentials. - VPN interference: Some VPNs inject a proxy entry in the system proxy settings during connection. Disconnect the VPN, run the reg delete commands above, then reconnect. I've seen NordVPN and OpenVPN GUI do this on Windows 10 22H2.
- Group Policy locked proxy: In a domain environment, IT might have forced a proxy via GPO. You can't change the settings manually. Check the LAN settings — if they're grayed out, run
gpresult /h gp_report.htmland look for "Proxy Settings" under Administrative Templates. If it's locked, only your IT can fix it (or you can try a local override with a REG_DWORDProxySettingsPerUserset to 0 inHKLM\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings, but that's a hack).
Preventing the error from coming back
Stop the root cause: avoid proxy-switching tools that don't revert settings. If you use Fiddler or Charles for debugging, always close them properly — they leave the proxy on. Set a reminder to check LAN settings after any VPN or security suite update. And if you're on Windows 11, note that the Settings app > Network & Internet > Proxy page can also leave a stale script address. Clean both places.
One last thing: if you're a developer who needs a proxy for work, use a dedicated browser (Firefox with its own proxy config) rather than system-level proxy. That way no system apps get confused. I've been doing that for years and haven't seen 0xC00D2EEE since.