RSC Sundae

I apologize in advance if this is the wrong board, but I seem to have an issue where I am unable to log in via the web browser (error: Sorry! Unable to connect...) while I have wifi and have chosen the correct server, yet I can log in via the legacy client.

What might I be encountering that is stopping me from playing on the web browser client? I have tried firefox and safari with the same outcome.

Thanks!
Arlo