2x Edit: Plugins should now be fixed, please force-update your server if they are still not working for you.
I believe this regressed with security updates. What plugin are you using / where did you get it from so I can take a look at how it loads?
EDIT: We just shipped an update that should fix plugins, but it's speculative in the interests of getting the fix out ASAP. If you are having this issue can you please force update your server and reply to let us know if it's resolved.
I tried csgo update MM/SM works fine. but
L 04/29/2021 - 11:19:50: [CSTRIKE] Sigscan for TerminateRound failed
L 04/29/2021 - 11:19:50: [CSTRIKE] TerminateRound detour could not be initialized - Disabled OnTerminateRound forward
It looks like TerminateRound signature is broken.