Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5cbcade4182a65.86959147", "IKMWheZPQ0As8OK8yVoSa1HFeMnOdmoc", "18.212.239.56", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: