Hello Admin and members of this forum, I was trying some functions related to sending email using php mail() function, and to my expectation, it didn’t work. But I used another web server, it worked perfectly. So please what could be the cause of this problem on this server. Thanks.
#Urgent Help.
Well, I hope this article explained your problem: https://infinityfree.net/support/php-mail/
In short, the PHP mailing system is intentionally blocked to prevent misuse (a.k.a spam behavior). We look for a broader view, not for one user only 
But hey, there’s always workaround for everything. Try to read the article a bit deeper.