When you import from an unpublished notebook, the cell shows a link to the wrong url.
In https://beta.observablehq.com/d/a531de411e58adf0 I do
import {hello} from "020b2e4be1504d1a"
which works.
But the link is to https://beta.observablehq.com/020b2e4be1504d1a, which doesn’t work. Should be https://beta.observablehq.com/d/020b2e4be1504d1a