"An authentication error has occurred (Code:0x507)" this kind of error you might have faced, usually you will get this error when you are accessing Windows Server 2008 OS remotely from Windows XP SP2 or SP3 ,Windows 7,Windows Server 2003, this error wont allow us to connect remotely, this happens because of NLA,and some Registry disturbance in local desktop, The solotion for it is:
1. Try to login with different user in that system where you used to code 0x507 error.
2.After login with other user name try to access remote of windows server 2008.
3.Now you can access Windows Server 2008.
Use the following steps if the above wont works for you.
1.Just rename the existing profile in that system.
2.Login with your id now and take Windows Server 2008 remote it will work fine.
Post comments if you got any issues
All The Best!!