If you're seeing the red text below after entering your TTB number, odds are you're not using the correct number. 

Be sure to enter your TTB registry number, exactly as it appears on page 3 of your approved Brewer's Notice:

Or if your brewery has been around since back when TTB was ATF, it'll be on the bottom of page 2:

Please double-check the number before clicking Next, so you don't accidentally get linked to the wrong brewery.

For more information about how Brewery Organizations work, go here.