Issue with Email List plugin

[R.IN.G.O Lavoro Over 40]

It's the first time I use it to send lines; until now I used it to send emails to selected addresses, that works well.

The popup windows is opened and shows, e.g., Email 2 records (that is right); I select the recipient and Send.
It is shown the message:

Message
0 emails sent

Notice
1 emails not sent
​

What is wrong?

 

[troester]

What are your "Addressbook" settings?
You should always include a subject and a message (otherwise it may create e.g. an "Empty message" etc. error or warning which may break something)

 

[R.IN.G.O Lavoro Over 40]

Hi, Troester.

Yes, I included a subject and a short message (the classical "Prova").
NB: the parameter Hide subject works on the contrary.