Corrupted cached data can cause loading errors.

: Go to the menu (☰) > Settings > Privacy & Security and change your protection level from Strict to Standard . 2. Allow Restricted Content or Pop-ups

Firefox may block a site if it detects security risks (expired certificates, known malware, phishing, etc.).

If the site works now, one of your extensions is the culprit. Press Ctrl + Shift + A (Windows) or Cmd + Shift + A (Mac).