Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5dd1a606a45479.67181573", "vwNcAQFRNPc4oVjFMqFt1hpRGMQXICmR", "34.237.51.35", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: