Php mail send problem

Welcome!
I am asking you that I have been able to send me an email to the free web hosting site so far. It would be exactly a class website where my classmates could send a message to the classmate. This email delivery did not work in the days. And I do not know what the problem is. Php does not write bugs. That would be my problem. Can I get some solution? Thanks in advance.
Postcards: I’m sorry if my English is bad, but I do not know much English.

The devs are fixing that.

In the night the email was secuessfully sent. Next day again bad! :frowning: