Expected router outlet to be a valid DOM Node (but got null) error

Does anyone know how to fix this? I tried the solution in this post: https://stackoverflow.com/questions/74928442/vaadin23-expected-router-outlet-to-be-a-valid-dom-node-but-got-null-and-homev, but it did not resolve the issue.
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Do you see any errors in the browser or server consoles?

@tireless-elk - any ideas?