Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5c6d6936d7d994.08570256", "UZj7jY1Yj7YL3fFpCddjtebeZx95jeKl", "18.206.175.155", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: