Logging into the web UI getting the error "HTTP Error 404 - Cannot connect to the server, please check API accessibility (certificate, API, proxy, etc)"

Solution In Progress - Updated 2017-11-15T23:08:21+00:00 -

Issue

Web UI was failing to authenticate after upgrading IPA packages. After testing for the known issues for the IdM WebUI failing after upgrades:
After upgrading from 7.3 to 7.4, Unable to access the IPA web GUI due to the error: "Login failed due to an unknown reason"
We see the following error:

HTTP Error 404 - Cannot connect to the server, please check API accessibility (certificate, API, proxy, etc)

Red Hat Enterprise Linux 7.4
Red Hat Identity Management (IPA)

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