Unable to sync with github account

I'm not being able to sync my vscode account.
Fedora Silverblue 33.

1. Turn on settings on sync.
2. On warning window, click in "turn on".
3. Sign in & Turn on
4. Sign in with GitHub
5. Login request redirecs to the browser (Mozilla Firefox in my case)
6. Authorize visual studio to access github.
7. Contunue
7. Browser shows "Authorization was successful. You will be redirected back to Visual Studio Code", but the request is not automatically redirected.
8. Follow the screen's instructions. Copy "Your authorization token"
9. Go back to Vs Code and click in "signing in to github.com". (Purple bar on window's bottom).
10. Paste token into the textbox at top of window and hit "enter".
11. Nothing happens. The message "Signing in to github.com" keeps at window's bottom and syncing process does't happen.

Start by reproducing the GitHub sign-in and settings-sync flow in Visual Studio Code on Fedora Silverblue 33, using Firefox for the browser redirect. Inspect the handoff after authorization and token entry; the issue is done when signing in completes and settings sync starts.

Written by the indexing model from the issue text.