Gmail users face blocked emails, triggering error messages without sender authentication. 

Neil Kumaran, Gmail's security manager, announced the policy to enhance email security. 

Authentication addresses loopholes exploited by attackers, aiming for safer inboxes. 

Google emphasizes robust email authentication for users sending significant volumes. 

Users receive error messages as Gmail enforces the authentication requirement. 

The policy, introduced in October 2023, targets a safer, less spammy inbox. 

Gmail focuses on closing loopholes exploited by attackers, affecting 1.8 billion users. 

The initiative responds to the need for a reliable source of emails without security worries. 

Gmail strives for a user-friendly experience, reducing concerns about email security.