Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5d12731712cd86.09424535", "SDOnhbl9EdsHdwac7xh7zBVs4JaaFsrI", "34.204.36.101", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: