Review request email button is disabled. Why?

I am doing some tests in OCS 2.3.6 and when i as director select a reviewer to a paper, i’m not being able to send the request review email to the reviewer beacuse the button is disabled. Why is it disabled? How do I eneble this button?

It worked!
I didn’t add myself as the director of the paper. I thought I did but didn’t.
Sorry for the dumb question.