The Pages report (formerly called Coverage report) in Google Search Console categorizes all pages Google knows about into four statuses:
Error - Pages that could not be indexed due to a critical issue. Common errors: server errors (5xx), redirect errors, blocked by robots.txt (unintentionally), submitted URL not found (404).
Valid with Warning - Page is indexed but has a problem. Common warning: indexed despite noindex tag (an alternate page was indexed instead), or soft 404 detected.
Valid - Successfully indexed by Google. This is the desired state for all important pages.
Excluded - Not indexed, usually intentionally. Includes: noindex pages, redirects, canonical non-selected, crawled/discovered not indexed, and duplicate content.
Click any status in the report to see the specific URLs and the reason for that status. Focus your attention on Error pages first, then review Excluded pages to confirm the exclusions are intentional.