Blocked crawler

The most likely cause is Snap URL Preview Service being blocked by your robots.txt or firewall. The crawler respects robots.txt, so a blanket Disallow: / kills previews.

Diagnosis checklist

1. Check robots.txt – look for rules blocking Snap URL Preview Service or all bots (User-agent: *).
2. Check for OG tags – curl your URL and verify og:title and og:image are in the HTML.
3. Check server-side rendering – client-side-only meta tags won’t be visible to the crawler.
4. Check HTTP status – must return 200 OK.
5. Check HTTPS – valid certificate required.
6. Check WAF/CDN rules – some firewalls block unfamiliar bot user agents.

Allowing Snap URL Preview Service

User-agent: Snap URL Preview Service
Allow: /

Place this before any blanket disallow rules in robots.txt.

Testing your fix

curl -A "Snap URL Preview Service; bot; snapchat; https://developers.snap.com/robots" \

     https://yoursite.com/page | grep -i "og:title"

If the tag is visible, wait up to 30 minutes for the cache to expire and re-share.