@Anonymous User
Welcome to the forum. If you've had a kids pass free trial in the past on a different account, or someone else in the household has had one using your payment card, then that would stop you getting another free trial.
If you don't think that applies to you try popping onto live chat, explain what's happened and see if they can help. You can get to live chat from the Contact Us page
https://help.nowtv.com/get-in-touch
(expand the Anything Else section at the bottom for options)
