Fix ERROR_CTX_ENCRYPTION_LEVEL_REQUIRED (0X00001B95) Fast

Why This Error Happens

If you're seeing ERROR_CTX_ENCRYPTION_LEVEL_REQUIRED (0X00001B95), your RDP client and the target server can't agree on how to encrypt the session. The server demands a minimum encryption level, and your client either has it set lower or doesn't have the right one at all. This is a classic misconfiguration, and I've seen it pop up after Windows updates, when someone tinkers with Group Policy, or when you try to connect to an older server (like 2008 R2) from a modern Windows 10 machine with a custom security policy.

Cause #1: Server Encryption Level Set to Low (Most Common)

In 90% of the cases I've fixed, the server is configured to use Low encryption level. By default, Windows wants at least High, unless someone changed it. When the server demands High but your client is set to Low (or vice versa), you get this exact error.

Fix: Set Encryption Level to High (or Client Compatible)

On the Windows Server (the one you're trying to connect to), open gpedit.msc and go to:

Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Security

Double-click Set client connection encryption level, set it to Enabled, and choose High Level from the dropdown. Click OK and restart the Remote Desktop Service (or the server). If you're on a domain, you might need to do this via Group Policy Management, but for a standalone box, local policy works.

The same setting lives in the registry if you prefer:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services
"MinEncryptionLevel"=dword:00000003

Value 2 is Low, 3 is High, and 4 is FIPS compliant. Set it to 3 unless you have a specific reason not to.

On the client side (the machine you connect from), make sure your RDP client isn't forcing a lower encryption. Usually, the default is fine, but if you've tweaked local group policy on your workstation, check the same path there.

Cause #2: Group Policy Override on the Client or Server

Sometimes you've set the registry correctly, but a domain policy overrides it. I've seen this bite people after their IT department pushed out a security baseline that set encryption to a specific level. The error appears suddenly on all machines that don't match that policy.

Fix: Check Effective Policy with RSOP

Run rsop.msc on the affected machine and drill down to the same security node. See what's actually applied. If it says Not Configured, then the local setting is in play. If it says Enabled, you need to align the policy or ask your admin to change it.

To force the local setting to stick, you can override the policy by setting the registry manually. But be aware that a domain policy will overwrite it on next refresh unless you also edit the policy itself. If you're the admin, modify the GPO that's causing the conflict. Look for the same setting name under Computer Configuration in the GPO editor.

Also, don't forget to run gpupdate /force after any change to make sure it takes effect immediately.

Cause #3: CredSSP or NLA Mismatch (Often Confused with This)

This isn't the exact error, but I've seen people mix up 0X00001B95 with the CredSSP error that says "encryption oracle" or "requires Network Level Authentication." The fix is different, but the cause is similar: a security setting mismatch between client and server.

Fix: Align NLA Settings

On the server, open Remote Desktop Session Host settings and make sure Network Level Authentication is enabled (or disabled) on both ends. If you're connecting from an old Windows 7 machine to a modern server, you'll hit issues. To fix, you can disable NLA on the server (not recommended for security, but works for troubleshooting), or update the client to a newer OS.

If you must keep NLA on, check the client's security package. For Windows 10/11, ensure you have the latest updates installed. The whole "encryption oracle" thing is usually a separate KB patch issue, but it's worth ruling out.

Quick Reference Summary

That should kill it. I've fixed this on dozens of servers over the years, and it's always one of these three. Start with the encryption level, then check policy, then stop chasing your tail. If you're still stuck after that, you're probably looking at a firewall or RD Gateway issue, but that's a different error code.