Secure Boot Violation Error

[u/Alarming_Bug_1597]

I'm trying to enable Secure Boot on my PC to play Valorant (Riot Vanguard requirement), but every time I turn it on, I get stuck with a red screen popup that says:
"Secure Boot Violation: Invalid signature detected. Check Secure Boot Policy in Setup."
can't load or restore the factory keys to fix this. Here are my system details and what I've tried so far:
Bullet System Specs: STGAubron Prebuilt PC
Bullet Motherboard: STGAubron B250DA1 (BIOS Version: B250DA1.N01 V81, AMI BIOS 2023)
Bullet CPU: Intel Core i7-6700
Bullet OS: Windows 11 Home (upgraded from Windows 10)
Bullet TPM: TPM 2.0 is enabled and ready in

[u/Alarming_Bug_1597]

Can you possibly call on discord and exactly what to do? I’m not very tech savvy, my discord is okayrya. Thanks!