SQL Datetime Not Equal To Is Not Working

I have a database consisting of a Customer, Product, and Transaction table.

I'm trying to write an SQL statement to list all customers' names and SSN's for those customers who have made no transaction in the year 2000.

The TransactionDate column in the Transaction table is a Date/Time data type (e.g. 2000-12-18 00:00:00).

This is the SQL code I've written:

SELECT DISTINCT CustomerName, Customer.CustomerSSN 
 FROM Customer, Transaction
 WHERE Customer.CustomerSSN=Transaction.CustomerSSN
 AND YEAR(TransactionDate)<>2000;
 

The not equal to symbol (<>) seems to not be working for some reason. When I change it to an equal sign, it does return the correct result...

Any advice is appreciated.

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