About submit: there is two buttons in the submit page: first for schedule submit, and 2nd for manual newsletter. Seems you’re pressing the manual newsletter send without introduce an email into de field…
I can send the manual newsletter (I introduced an email into the field).
I have made a mistake. Yes, there are two buttons. I did not know, that the button for schedule submit is also the right button for immediately newsletters. (Schedule menas in Future for me).
That was a misunderstanding.
Thank you very much for your help.