Here’s the working solution to Vxdiag Benz C6/VXDIAG multi tool Xentry software software error”
No Access authorization code!  You must contact the User Help Desk”

Solution:

If you install VXDIAG 2TB hard drive comes default with the package, there is a Tool folder on desktop

Open 1-StartKeyCenter and 2-Key, fill in hardware ID and date.  Then generate a Starkey with Xentry Developer Keygen.

Enter the Starkey and fill in the corresponding area

Then save key.

xentry-no-authorization-code-5

If xentry prompts message above which indicates the registration is succeed.