Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5cbcad6bdcfbe6.02509231", "qNAz0ua2jpJyXU8hobprNUSfb7EQHwCr", "18.212.239.56", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: