Fatal Errors on pluggable.php

Don’t mess around with changing those files directly. It will break when that file gets changed in an update. Do this instead.

add_filter( 'wp_mail_from', 'override_mail_from_address' );
add_filter( 'wp_mail_from_name', 'override_mail_from_name' );

function override_mail_from_address($email_address) {
    $from_array = explode('@', $email_address);
    $from_address = $from_array[0];
    $from_domain = $from_array[1];

    if (strtolower($from_address) == 'wordpress') {
        $from_address = "myname"; /* Put the email address you want here */
    }

    return ( $from_address . '@' . $from_domain );
}

function override_mail_from_name($email_name) {
    if (strtolower($email_name) == 'wordpress') {
        $email_name = "My Name"; /* Put the name you want here */
    }

    return ( $email_name );
}