Fonts are all active
This check makes sure that all fonts that are referenced in the document are currently active on the Mac and available to be used by InDesign.
To see a list of missing fonts choose the Type > Find/replace font
Fonts with a warning symbol are missing.
Fonts activated through Adobe Fonts (formerly Typekit) are not missing and are not flagged by this check.
To activate fonts on your Mac we recommend using professional font management tools such as Extensis Suitcase, or Font Book, which is a free font management tool that comes with your Mac.
Fix this problem by finding and activating the fonts used in InDesign or in some cases by substituting for other fonts.
Adobe InDesign Font help
Apple FontBook help