Fix: RDP Authentication Error has occurred issue in Windows 11 / 10

Connecting to the remote server from a machine works usually very smoothly. But, sometimes you may see this annoying error message on your screen saying “RDP Authentication Error Has Occurred – The Function Requested Is Not Supported“. If you have recently upgraded your system, this error may appear before you. Follow these easy fixes to solve this problem quickly.

Fix 1 – Turn off NLA on Remote Desktop

You have to remove the Network Level Authentication requirement from the Remote Desktop connection.

1. At first, press the Windows key+R keys together.

2. Then, type “sysdm.cpl” and click on “OK“.

 

Sysdm Cpl Min

 



3. When the System Properties window appears, tap on the “Remote” section.

4. Now, uncheck the “Allow connections only from computers running Remote Desktop with Network Level Authentication (recommended)“.

 

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5. After that, tap on “Apply” and “OK” to save these changes.

 

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Finally, try to connect the RDP client to the remote server. This shall solve the problem you are facing.

Fix 2 – Enable the Encryption Oracle Remediation policy

You have to enact this policy on the remote deskop client machine.

1. At first, press the Windows key+R keys together.

2. Then, type “gpedit.msc” and hit Enter.

 

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3. When the Local Group Policy Editor opens up, navigate to this section –

Computer Configuration > Administrative Templates > System > Credentials Delegation

 

4. On the right-hand side, double click on the “Encryption Oracle Remediation” policy.

 

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5. After that, set this policy setting to “Enabled“.

6. Then, click on the ‘Protection Level:’ and choose “Vulnerable“.

 

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7. Finally, tap on “Apply” and “OK“.

 

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Close the Local Group Policy Editor screen. Then, restart your system.

Now, try to connect to the RDP server once more. If this doesn’t work out, go for the next fix.

 

NOTE

If you are using the Windows Home version, you can’t change the policy on your system. So, follow these instructions instead.

1. At first, click on the search box and type “cmd“.

2. Next, right-click on the “Command Prompt” and tap on “Run as administrator“.

 



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3. Now, copy this code from here and paste it in the terminal, and hit Enter.

reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters" /f /v AllowEncryptionOracle /t REG_DWORD /d 2

 

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This will modify the registry on your system simply by changing a particular value.

After that, close the Command Prompt terminal and restart your system.

Upon rebooting the system, try to connect to the RDP one more time.