If you need to browse your SharePoint using Firefox then as Standart you need to enter your Logon Credentials. Reason is that NTLM is not activated. To change that follow these steps:

  • open Firefox and navigate to: about:config
  • a warning will pop up – press ok
  • search for network.automatic-ntlm-auth.trusted-uris
  • double click & insert your URI: example.com
  • Restart Firefox