A route or day view won’t generate

The most common causes, in order of likelihood.

You’ve hit the daily limit. Free accounts get 1 route generation and 2 day-view generations per rolling 24 hours; guests get fewer. Signing in, or upgrading, raises or removes the cap.
The day view needs a chosen route first, generate or select a route candidate before trying to generate the day-by-day view.
A very long or unusual date range can occasionally need a retry, if a generation fails outright rather than returning a limit message, try again once before assuming it’s broken.

If none of that explains it, the chat in the corner of this page can look at what’s actually happening on your account, or flag it to a person if it’s a genuine bug.