@KevinH
I extracted Noto Sans .woff and .woff2 fonts from a
Noto Sans NPM package and had no problems adding .woff and woff2 fonts to new epub2 books.
@jreckard
If you took the .woff fonts from a commercial .epub file, they might be obfuscated.
If you open .woff or .woff2 files with a hex editor or Notepad++, the first 4 characters should be wOFF and wOF2.