Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5c968c4c5124b1.92502089", "TM25KOgcOYfUhIqd6oiGKD28KSfkbTJH", "18.206.168.65", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: