this is a recurring problem - it works with some release then not with the next - it is likely an upstream issue - ive reported the bug myself in the past - it gets fixed then it comes back

the only apparent clues are this line in the shell terminal:
<pre>
console.warn: LoginRecipes: getRecipes: falling back to a synchronous message for: https://accounts.firefox.com
</pre>

and this error in the browser JS log
<pre>
Working…
Response not received for: fxaccounts:can_link_account
</pre>