I have installed SDL Web 8.5 and while trying to browse the Content Manager Explorer, it does not load it (appears loading). Any help would be really appreciated.
I've seen 404 errors being reported by IIS instead of 500 (some sort of security factor from IIS). If you have a 404 on a GET (all I see in your images are POST) can you try calling that URL directly? IIS may then give you more details on the actual cause of the error.
Top left hand corner, there is the settings\flyout button, click on it, you should get a flyout, click on Content Explorer in the flyout. I think you may find the CME show up or a more specific error.
Have you restarted the machine after SDL Web CM installation? If you have already tried so, could you please provide some more details regarding the error by checking in the
eventviewer -> applications -> Tridion logs
Update1: Also, Please verify your browser settings are correctly configured to allow popups Configuring your Web browser for Content Manager Explorer
Update2: From your new screenshots, I can see that you are not able to start the discovery service successfully and the reason for that is you have configured the OAuth credentials wrongly in your . Solution : either update your OAuth user credentials properly Content Delivery OAuth authentication frameworkor disable the OAuth for now following the Disabling OAuth authentication(for all microservices, recommended only for testing purposes)