7-port USB hub only partially activated on XP PC

Hi — Just installed the powered 7-port hub (with 3 charging ports) on an old machine running XP-SP3. I plugged it into one of the USB 2.0 Root Hub ports.
The PC recognizes only the first 4 ports of the hub. I’m assuming that is what shows as a new “Generic USB Hub” in the Device Manager (4 ports). That portion of the 7-port hub is started by the PC and is active. However, there is also a 2nd “Generic USB Hub” (feed + 3 ports) which cascades off the first which does NOT start and returns a “power exceeded” error message. All of this happens with NO devices plugged into the hub.

Why would I receive a “powered exceeded” message for this 2nd set of ports when the 7-port hub is has its own power? Granted the PC is old, but the hub should work from what I can see. What could be causing the PC to ignore that the hub is a powered hub?

By the way, I tried the hub on a Mac laptop and the entire hub (7 ports…i.e., both cascaded sets of 4 ports) is started and available.

Thanks for your thoughts.

— Brian