Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5cbcacf3ab2ad5.14007692", "xq5fX1Nnd2TS8Hiil7iVeQMOdjD1Mvlq", "18.212.239.56", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: