When I enter My ITIN # where it asks for my SSN it says invalid SSN

You should be able to enter a valid ITIN in the same entry field where you would enter a Social Security Number, as stated in this help article. Double-check to see that the number was entered correctly.

All valid ITINs are a nine-digit number in the same format as the SSN (9XX-8X-XXXX), begins with a “9” and the 4th and 5th digits range from 50 to 65, 70 to 88, 90 to 92, and 94 to 99. See this IRS presentation for more information.

If an ITIN isn't used on a U.S. federal tax return for any 3 consecutive tax years, it expires on December 31 after the third tax year of non-use. See this IRS webpage for more information.

Check your tax records in your IRS Online Account.