According to ASRock CPU List for your Motherboard you need BIOS version P4.10 or newer installed to support your Ryzen 3 3100 processor: http://www.asrock.com/MB/AMD/B450%20Pro4/#CPU
BIOS Version P4.10 came out on 03/27/2020 so if you motherboard is older than that date you probably will need to update the BIOS to support your processor: http://www.asrock.com/MB/AMD/B450%20Pro4/#BIOS
The motherboard should have a sticker on there somewhere showing which BIOS Version the motherboard has installed from the factory.
Also the BIOS Version could be stamped on the BIOS chip on your motherboard.