How to fix an authentication error has occurred the function requested is not supported error in Windows

Installing the latest Windows update can fix the "an authentication error has occurred the function requested is not supported" error message. Check if a Windows update is available, and if one is available, download and install it.

If you are not sure how to check for updates manually, and update your device's operating system, feel free to check out the how to update the operating system guide.

If the computers aren't connected to the same network, this error may be the result of an unstable Internet connection. Make sure that the Internet connection both the devices are connected to is strong and reliable (you can check this on websites like speedtest) and attempt the process again.

To improve the Internet connection, you may do the following:

• Bring your computer closer to the router;
• Use a signal booster;
• Buy a stronger router;
• Connect your computer to the router using an Ethernet cable.

Despite the numerous security benefits of firewalls and antivirus software, on rare occasion, they may cause errors like this one.

To verify if the antivirus or firewall is the reason behind the error message, you can disable them temporarily. If the error message didn't appear, access the firewall and the antivirus settings and check how they are configured. Also, you can go through help articles which can be found on the developer's website or in the operating system.

To disable the Windows Firewall, you can follow the instructions below:

1. Go to the start menu and type Windows Firewall;
2. Click on Windows Firewall and then Turn Windows Firewall on or off;
3. Click on Turn off Windows Firewall (not Recommended) under Private and Public networks:
   
   

To enable the Windows Firewall,follow the steps below:

1. Go to the start menu and type Windows Firewall;
2. Click on Windows Firewall and then Turn Windows Firewall on or off;
3. Click on Turn on Windows Firewall for both Private and Public networks;
   
   

Although temp and system files are meant to do good and improve your computer's performance, they do quite the opposite if they are corrupt. Maybe corrupt system or temp files on one or both of the computers are the reason behind this error. These issues can be resolved through the Disk Cleanup tool by Windows with which you may remove corrupt files.

To run the Disk Cleanup tool, and remove redundant files, feel free to follow the steps below:

1. Go to Start menu and type Disk Cleanup in the start menu search box;
2. Select the drive you want to clean up first by clicking the small arrow and click OK;
   
   

   
   
   

3. Under Files to delete, select the file types to get rid of (by ticking the checkboxes next to them) and click on OK.
   *Repeat this for each drive separately ( "C:" "D:" "E:" and etc.).

   
   
   

The router, or the modem, if you use one is the entry point of Internet access in every household. If they don't spread the Internet connection well, then you won't be able to access the Internet, and among the rest to connect to the other computer. It is possible that your router, or modem, or both got "stuck" and as a result, the error message appeared. Maybe there was a sudden cut of Internet access, and your router/modem failed to reconnect.

Restarting the router and modem would do the trick. For even better results, you can unplug them from the power strip, and plug them back in after 2 minutes.

Modifying the Encryption Oracle Remediation policy can help you address the "an authentication error has occurred the function requested is not supported" error message.

To modify this policy, feel free to follow the steps below:

1. Press the Windows and R keys on the keyboard, type gpedit.msc in the Run window and hit Enter;
2. Find and click on the Credentials Delegation folder, by opening the folders below in the left window pane:
   
   Computer Configuration > Administrative Templates > System
   
   
3. Find Encryption Oracle Remediation and double-click on it;
4. Click on Enabled, under Encryption Oracle Remediation;
5. Click on the drop-down menu next to Protection level; and select Vulnerable;
6. Click on Apply and OK, to save the changes;
7. Restart the computers.

Modifying the AllowEncryptionOracle value in the Registry Editor (regedit) can help you fix this error message. Follow the steps below to edit the registry value, but proceed with caution, as editing the wrong file in the registry editor can result in system instability:

1. Go to the start menu and type regedit;
2. Click on the folders in the left window pane, to access this location:
   
   HKLMSoftwareMicrosoftWindowsCurrentVersionPoliciesSystemCredSSPParameters
   
   
3. Double-click on the AllowEncryptionOracle file, located in the right pane, set the value data to 2 and click on OK;
4. Restart your computer.