Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5cbca6d76f2ae5.35175328", "RjxQfDEUGw0H3Kx9MemXlP1ACkdNjQVP", "18.212.239.56", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: