PHP mail() function not sending emails: causes and solution

Hello everyone! I'm a beginner PHP developer and I'm having a serious problem with sending email via the mail() function. On my local server (OpenServer) everything worked perfectly — emails arrived instantly. But when I uploaded the project to a real hosting, the function stopped working: it returns false, and there are no errors in the logs.\n\nHere is my code:\n\n```php\n\n```\n\nThe email does not reach any mailbox — neither Gmail nor Yandex. At the same time, on