AutoCAD 2010/2011/2012 DWG Format

[#1]

A valid license could not be obtained by the network license manager

Error[-15.570.0] Please see Attached file

I'm a new comer, I'dont know that what happened this problem 

Please help me out.

[#2]

Did you ask your network administrator?
Is this a new problem?
Is your PC disconnected from the server?

[#3 · Accepted solution]

It's likely an IPv6 issue.  For more information about Network License Manager connectivity issues and IPv6, please see my discussion post here:

http://forums.autodesk.com/t5/Installation-Licensing/Network-License-Error-1-5-15-and-IPv6/td-p/2982...

[#4]

finish. Thank you so much