When attempting to RDP to a server, you may receive the below error:

Authentication Error Has Occurred. The function requested is not supported

There are a couple of ways you can resolve this issue:

Option 1:
1) Click start, click run, type gpedit.msc and click ok
2) Browse to Computer Configuration > Administrative Templates > System > Credentials Delegation > Encryption Oracle Remediation
3) Within Encryption Oracle Remediation click enable and change protection level to Vulnerable and click apply

Option 2:
1) Click start
2) Locate My Computer or This PC depending on your OS version
3) Right click and click properties
4) Click advanced system settings
5) Click the Remote tab
6) Untick the box ‘Allow connections only from computers running remote desktop with network level authentication’
7) Click ok