Crashing on loading screen

When I go onto my Minecraft launcher I see that pretty much all the versions don't support some sort of security thing on Mojang. I assumed that was normal and just clicked play on the 1.16.5 version. Then when it's loading on the Mojang screen it gets 3 quarters of the way then Mojang just crashes. I've reinstalled Minecraft, I've restarted my pc and I don't know what else I can do.