[Plugin: WP Breaking News Mail] plugin not work without login

If i login with any account it’s work fine , i easily subscribed my emailID but when i subscribed another Email ID without login it show massage 0 (Zero) , i don’t understand what’s happen , my second problem is no any mail goes to user after a new post done , is there any setting will be done before post , at present no any change on setting done , i am new one in wordpress plz advise me

https://www.ads-software.com/extend/plugins/wp-breaking-news-email/