Issue:

I have generated a license by putting letters of the Hardware ID and the error I am getting is "Your hardware ID doesn't match the hardware ID specified in the license".

Cause:

Hardware IDs are case-sensitive. The problem is you have used lower-case HW ID to generate the license. 

Solution:

Hardware IDs from SDK should be upper-case the way they are displayed in LicenseManager. You should copy HW ID printed in LicenseManager and use it to generate the license.