I seem to be having a similar issue… I can access my dev environment but not staging or production (both on Heroku)
Repros in Chrome and Safari
Looking at network requests… Forest seems to be getting a 500 when making a request to [my-server]/forest/authentication
My staging application_url: https://dispatch-er.herokuapp.com
Could you please create a new thread and tell us the configuration of your project and the different forest versions it uses?
This will make it easier for us to investigate your problem and deal with it.
Thanks a lot!