I was wrong, registrations and send password stoped working also with the same email error.

I get the following message when I try to make an announcement and create an event.

The email could not be sent to *****@****.com

The following error occurred:
You must provide at least one recipient email address.

Messaging working just fine.

I am trying to install this plugin and after checking existing fields (step 1 and step 2), page refreshes and nothing happens. What can be the problem?