I've been successfully using Norton 360 since 2015. This week I tried to access the server to install my third license to my new PC, but I failed.
What is going on? It sounds like a violation of license agreement.
What error messages are you seeing when you try to install?
Did you ensure you still had the activation available? From your Norton Account, click on the user icon at the top right and click on Manage My Subscriptions. Then find your current subscription and click Manage Licenses. Be sure you still have one available there. Or remove any un needed devices by clicking on the trash can beside that license.
Are you logging into your Norton Account from the new computer, and clicking on Download? That should download and install your product.