The iLO app is scoped to read the redfish DMTF data using the app-redfish library. Currently, the app-ilo only understands newer HPE Gen10 servers but the app-redfish should be able to pull any and all DMTF data from whatever the source. The layout and the format is a bit specific in app-ilo and my assumption is that Gen8 gear isn't in the same layout. Hence the 'Item not Found' error.
It is possible though, that it is authenticating correctly and that the app-ilo only needs to be tweaked to allow for the proper schema. If you want to help us improve this fully open source app, you can start by hitting your Gen8 or Gen9 box with a program called 'Postman'
For example, my get request in Postman for Gen10 looks like this:
I'm using 'Basic Auth' with the administrator username and password for iLO.
Here is another great utility for exploring the schema. Unfortunately it does not have the MicroServer Gen 8 but from what I understand, the MicroServer Gen 8 is more of a Gen9 iLO schema. I could be wrong though:
If you are interested, we can explore doing a backwards compatibility project in the community but HPE's interest in doing new dev work on old platforms is low.