In older ESET versions, go to Advanced setup → Authentication → Enter the username and password exactly as provided. Avoid using the license key format in username fields.
No. Your real-time protection still works with the existing (old) signature database. However, you are not protected against new threats since the last successful update.
Stay safe, stay updated.
When ESET tries to update, it connects to ESET’s update servers. The software sends your license credentials (username, password, or license key) to authenticate. If the server rejects these credentials—or if something blocks the secure handshake—you get the "authorization failed" error.
Every time it updates – usually every 1-2 hours. If authorization fails repeatedly, your protection becomes outdated.