Access denied opening parentPageUrl, WebAppURL, or SnippetURL

[rstrahan]

After stack completes, attempt to open ParentPageUrl fails with error:

<Error>
<Code>AccessDenied</Code>
<Message>Access Denied</Message>
<RequestId>1D7247125DABCC0B</RequestId>
<HostId>
eif4IhxexB9KxvoPyIo8i1qbpDzMG8LPoDx0TLV8C0JTb/1HAgwzcQc9PkXnr/LxoBGDLeyLKUQ=
</HostId>
</Error>

On closer examination, opening CodeBuildUrl shows CodeBuild step has failed, running 'npm update -g npm'
see screenshot below.

This seems like a new issue - not encountered recently when i last installed the UI.