Windows 11 Lenovo Laptop not sleeping when I close the lid

I have a Lenovo Ideapad Slim 3 that I bought new two months ago, and it is running Windows 11. I have no idea why, but starting a few days ago, whenever I close the lid of my laptop, it doesn't sleep. This winds up draining my battery to death when the lid is closed. I don't know why this is happening but it did seem to only start to occur after I installed an update to Windows 11 - I update Windows 11 every few weeks because my computer tells me I should. Does anyone know how to get my laptop to actually sleep when I close the lid so that it doesn't drain the battery?

Question by Ben on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.