Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5cbcaa9a1e9894.48555710", "g7r98fMH9BGCNpmYRLPmz0TzKZFQnVDu", "18.212.239.56", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: