Noise Reduction selection no longer an option

Good afternoon from the UK.

I'm new to Audition and have been following various tutorials on YouTube to learn how to use the software.

After recording some Audio for the first time and hearing a hissing throughout in the background, I decided to look into Noise Reduction. I followed all the instructions and initially this worked.

Now in creating a new recording and selecting a sample, it won't let me click 'noise Reduction or/Capture Noise Print' at all. I've tried without selecting first and then with selecting. I've tried in and out of a recording format. I am in the Podcast format if this makes any difference.

Can anyone suggest where I'm going wrong?

Jen