@Mikhail Thank you for contacting us!
In this case, the Login tab opened and since there was no action, it timed out.
Can you please refresh the web browser as that would enable the Login button again, clicking on which will open a login tab and you should see the device code to be entered as has been captured in the screenshot below:
While this fix has been taken for the time being, we are working on an inline UX change for showing the device code upfront as it no longer shows up automatically in the new tab that opens.