Error sending emails from Drupal 8

Sending an email using PhpMail->mail method, the headers are encoded with static method Unicode::mimeHeaderEncode.
The From header containing a string 'Morský' (from the web page title) is encoded as well, but this encoding creates an error when sending with php mail() function and Drupal is rendered unable to send emails.

core\lib\Drupal\Core\Mail\Plugin\Mail\PhpMail.php