php - The e-mail header from the online form is displayed incorrectly

I have a questionnaire form on the web. After filling in this form, I send it to me by email, using the PHP function mail(). The form body and the data it contains, including the private message are displayed correctly on gmail.com. The problem, however, occurs in the header of the email itself. Some characters are displayed incorrectly.
Here is a sample header:

$headers = "Content-Type:text/html; charset=utf-8\r\n";
$headers .= "From:" .$email . "\r\n";
$headers .= "Reply:" . $email . "\r\n";
$headers .= "X-Mailer: PHP/". phpversion() . "\r\n" ;

Required display of email subject:

Nový dotaz -- námět, od Fořt Petr 

Simultaneous displaying of the subject:

Nový dotaz -- námÄ☒t od: FoÅ☒t Petr 

The squared times symbol is more like a rectangle.

Is anything wrong? Or where should I look for a mistake?

Answer

I'm not sure \r\n works on all platforms

see : Which line break in php mail header, \r\n or \n?

instead

("xxx\r\n\yyy");

use

Header('xxx');
Header('yyy');

or use PHP_EOL, not "\r\n"