You downloaded a Japanese font (like Kosugi Maru) that lacks Traditional Chinese glyphs. Solution: Re-download a true TC version. Look for files labeled TC or TW in the name.
How to Download and Use Yuanti TC: The Perfect Rounded Chinese Font yuanti tc font free download
: Another free alternative derived from the Klee One font, providing a friendly, rounded look. You downloaded a Japanese font (like Kosugi Maru)