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16gb of my 32gb RAM memory is “hardware reserved” and not usable

I have a B450 GAMING PRO CARBON AC (MS-7B85) motherboard and for three years I have been using 16gb ram (Corsair 16GB (2x8GB) DDR4 3000MHz CL15 Vengeance LPX) without any issues. Today I decided to buy 2×8=16gb more RAM (the exact same product as before). I put them in to the remaining last slots firmly securing them in place. When running dxdiag, the memory seems to be recognized:

dxdiag

However, in the task manager only 16gb is available and it says that another 16gb is “hardware reserved”:

Taskmanager

This is the information in the BIOS:

BIOS

How do I enable all of my 32gb of ram?