[Plugin: ALO EasyMail Newsletter] Cannot Send Messages?

Plugin is not working on one of my sites. I have ALO EasyMail Newsletter installed on 3 other sites and is working fine.

When I try to send a message nothing happens. Test or Send Now.

I deactivated ALL other plugins and reinstalled manually vis FTP to no avail.

Any settings I am missing?

https://www.ads-software.com/extend/plugins/alo-easymail/