I just updated AE to 12.1, and now no fonts work in it. I originally got the error "Unable to load font "^0" "Helvetica Neue," but got that one resolved only to get "After Effects Warning: Unable to create font." This happens for any area of a comp that has text. No video will display at all where I have text.
The fonts are activated. I did find that some of them had somehow turned off since yesterday. I'm using FontExplorer X for font management.
They worked just fine yesterday in 12.0. Frustration factor high on this one.