Note that there are some explanatory texts on larger screens.

The database sent an unexpected error, this is likely a bug.
A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 35 - An internal exception was caught)



SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).