Don't worry as I'll be glad to help, After reading your post, I did go through the Product specifications of your product and found that HP Thunderbolt Dock 120W G2 is not compatible with your computer.
Hope this helps! Keep me posted for further assistance.
Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".