By default Windows 7 doesn’t support DES encryption, so this can prevent kerberos authentication from working.
So to enable DES encryption support we need to do following configuration at Windows 7 client machine.
Go to Local Security Policies(By typing “Local Security Policies” in run dialog)->Local Policies->Security Options->Network security: Configure encryption types allowed for Kerberos:
Here select checkboxes against DES_CBC_CRC, DES_CBC_MD5 and RC4_HMAC_MD5.
Refer below snap:
After doing this configuration you should be able to successfully run kerberos authentication at your Windows 7 client.