Unsolved: My snap to face isn't working, can anyone help?

[Boom bang man]

I'm following blender guru's tutorial and suddenly my snap to face doesn't work. It worked just fine before but then it didn't. I tried uninstalling, turned on all the addons, installed old versions, make new models, but it doesn't work. I'm completely lost, any help would be great.

[Shark]

Hard to tell without having a screenshot of your snapping settings, but if I had to hazard a guess, is any of the boxes checked for "Backface Culling / Project Onto Self / Align Rotation to Target / Project Individual Elements" ?

Sometimes they cause snapping to act a bit weird

[The Renderer]

It doesn't suddenly stop working, so you are doing something wrong, but as Shark said above, it's hard (impossible) to tell what that is without more info from you.