Cannot access Server Manager - "unauthorized access"

[MichaelBell]

I've just installed ArcGIS Enterprise using the Enterprise Builder - so this comes with ArcGIS Server, Portal, two webadaptors (server and portal), and Datastore.

I can access Portal just fine using the credentials that I was asked for during the install, however I cannot access the Server Manager. I keep getting an "Unauthorized access" message, as below:

Anyone got any ideas? This is the last part in this (very long) saga I feel, as I just need to get into Server Manager and register my data source.

[ReeseFacendini]

If Enterprise is version 10.8.X or later, Data Store sources can be added through the Portal for ArcGIS UI as well as Server Manager.

Add /New Item -> Data Store, and follow the prompts to add a folder, database, or Cloud Store connection.

[MichaelBell]

That's worked pretty well, thanks. And somehow I can access it on my server machine too!