Does Piwik support error monitoring. I mean, for example, if web server will return 404 error, will piwik say that?
Piwik can track 404 errors, if you import your server logs with our Log Analytics tool
If you use the Javascript tracker you have to track 404 pages specifically, see guide at: How to track error pages (404 pages) in Piwik? Which URLs are 404 and which referers lead to these pages? - Analytics Platform - Matomo