After filling out the signup form and clicking “Create your account”, the modal dialog gets a red header bar with the message
Something went wrong, perhaps this email is already registered, try the forgot password link
This happens with any mail address. I have no blocked email domains.
The browser’s network log shows a request to https://example.com/u receiving a 400 error and the response {"errors":["param is missing or the value is empty: email"]}
https://example.com/logs/ shows nothing remotely related I think, maybe some Job exception: Net::SMTPServerBusy errors from 3 hours ago.