Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5d126d715b7885.44168641", "qPQbN51s3N9QNCs0vRB9eMbuZaufG1qS", "34.204.36.101", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: