The issue could be due to browser cookies, refer to the below documentation for initial troubleshooting :
Unable to Connect to VMware Cloud on AWS
1. Check and try in different browsers to isolate if this issue is with the browser.
2. Press F12 in the loading screen of the Tab and under Network - capture if it is throwing any errors.
3. Collect a HAR file for further log analysis and to perform advanced troubleshooting. How to Collect a HAR File and HTTP Error Logs
4. In Chrome - change the option 3 samesite as Disabled. To do this on the browser > go to chrome://flags/
Then reload the browser, this will close /reload all tabs - then try accessing the Networking and security tab.
Workaround:
If this issue is seen only in Chrome, it is likely due to recent security enhancement on the new version of Chrome.
We can see a warning like this on F12 dev console if it's applicable.
For instance, a warning like:
console/sddcs/aws/xxxxxx< SDDC ID >xxxxxxx/networking-and-security:1 A cookie associated with a cross-site resource at https://nsx-x-xx-xx-x.rp.vmwarevmc.com/ was set without the `SameSite` attribute. It has been blocked, as Chrome now only delivers cookies with cross-site requests if they are set with `SameSite=None` and `Secure`. You can review cookies in developer tools under Application>Storage>Cookies and see more details at https://www.chromestatus.com/feature/5088147346030592 and https://www.chromestatus.com/feature/5633521622188032
https://www.chromium.org/updates/same-site - Right now, the Chrome SameSite cookie default is: “None” which allows third-party cookies to track users across sites. But from February 2020, cookies will default into “SameSite=Lax”
Any cookie with the “SameSite=None” label must also have a secure flag, meaning it will only be created and sent through requests made over HTTPs. Meanwhile, the “SameSite=Strict” designation restricts cross-site sharing altogether, even between different domains that are owned by the same publisher.