Do you maybe have the Honeycomb throttle? And is your throttle AP still on the VS switch? It might force it on VS mode and then it isn’t capable of switching to APR mode.
Your descent should start at 7.5nm at 2500ft
You are already closer than that, so you are potentially outside of the GS beam. Try again, and fly at 2500ft steady. When you are at about 8nm out, click the APR button. Let us know how that goes.
Can you stream? I can watch along and help.