I have the same or similar issue. I have used the personal version of Fusion on an iMac for quite a few months(First iMac i7 5K, 48Go Ram, 2To SSD, Catalina, and now iMac Pro Xeon 32, 5K, 64Gb Ram, 1To ssd, Sonoma). Since the very beginning I could not restart Fusion if I quit the application, I had to launch the service utility to repair the installation and once this done I could open it again and this on the two iMacs. Today I had a different issue, Fusion didn't want to start (as usual) but also the utility application didn't want to start too, so I removed Fusion and downloaded a new version (Personal), When installed and launched, it redirects me to the Autodesk login on the web, I do so and it is meant to redirect me to the App to complete the launch, but The Application connect screen stays on for a (very) long time before telling me that the connection didn't work and I should try again... I tried maybe a dozen times before trying to have a chat with an assistant, but this was no help at all. I then looked for a possible help on the web and here I am !
The network diag tool tells me that connecting to:
https://notifications.api.autodesk.com/health is orange
https://www.autodesk.com/products/fusion-360/collaborator is red
https://clientstream.launchdarkly.com is red too
all the rest has the green tick mark on.
Then a message in red saying that I have network connection issues and I should check... bla bla bla bla... I have no anti virus, no vpn, no firewall installed, nothing which could suddenly block Fusion to enjoy connecting to the rest of the world... I have been a developper, then a network guy for the last 40 years so I am a bit computer literate, although I am French.
I really would love to have Fusion working again on my iMac, I just tried to launch it on my laptop (MacBookPro 13" M1 8Go 1To) and it works.... but it is a lot more comfortable to use my 27" 5K screen than the Laptop 13" screen !!!
Any help will be greatly appreciated !!
Charles