Hello @Anonymous
Sounds like your proxy settings are enabled on your machine forcing you to authenticate when accessing the internet.
* If you are not using a proxy server to access the internet please do the following:
- Make sure your LAN Settings match the LAN Settings in following link.
https://knowledge.autodesk.com/search-result/caas/sfdcarticles/sfdcarticles/Meta-licensing.html
- Check your system variables to make sure you do not have http_proxy. If you do, please remove this variable. For steps to locate your system variables please refer to the link.
https://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/Installing-and-loading-Fusion360-in-a-proxy-environment-you-are-seeing-No-user-logged-in.html
* If you are using a proxy server to access the internet please do the following:
- Configure your proxy server so that anonymous access is open to the domains in the link below.
- Make sure your proxy server is able to connect to the list of domains\host on ports 80 and 443
- Make sure your fire wall or antivirus software is not blocking access to the domains listed in the link.
How to resolve network connectivity problems for Fusion 360
https://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/Network-Configuration-for-Fusion-360.html
Please "Accept Solution" if a reply or replies have helped resolve the issue or answered your question, to help others in the community.

BHurley
Autodesk, Inc.