Hello,
Since yesterday I have transferred my website from Hostinger to 000webhost, but now sending emails from the site no longer works. The emails do not arrive. According to the statistics they would have been sent.
What could be the cause of this.
Greetings.
It could be the destination server is blocking 000webhost as lot of provides do so unlike Hostinger? 
What is the script looking like?
sorry, where can I find that?
I have no knowledge of such things at all.
What does your script look like you use for the mailings?