As you can see from the image above the reply dialog is not up.
I get the app in this state by:
- Clicking the thread subject link in the email alert
- Clicked reply
- Page reloaded, i guess it is logging me in.
- Clicked Reply Again
- Clicked Mark as Answer. The reply dialog went away
- Clicked Reply. The error displayed
To get out this infinite loop, I simply refreshed the page.