PHP发送电子邮件GMAIL错误

我正在尝试使用php发送电子邮件。

public function email($to, $title, $message){
        $from = "me@mysite.com";
        $headers = "From: {$from}'r'n";
        $headers .= "X-Confirm-Reading-To: {$from}'r'n";
        $headers .= "Reply-To: {$from}'r'n";
        $headers .= "Organization: InfiniSys, inc.'r'n";
        $headers .= "MIME-Version: 1.0'r'n";
        $headers .= "Content-type: text/html; charset=ISO-8859-1'r'n";
        $headers .= "X-Priority: 3'r'n";
        $headers .= "X-Mailer: PHP". phpversion() ."'r'n";

        $subject = $title;
        mail($to, $subject, $message, $headers);
    }

消息发送；然而，gmail给了我一个错误。"Gmail无法验证mysite.com是否真的发送了这条消息（而不是垃圾邮件发送者）"。

SPF记录：（我不知道这是什么）

SPF record lookup and validation for: rrh.com
SPF records are published in DNS as TXT records.
The TXT records found for your domain are:
v=spf1 include:spf.protection.outlook.com a:mailman1-eqix-sjo.packet8.net a:mailman1-eq.packet8.net -all 
google-site-verification=GDHGdTnww1rIsh46Zd-n7I-E6d6Fa1n83XZ0ppfx4e8 
MS=ms49526710 
google-site-verification=-O2gI7Ji-rmEFlZQq8d85jHef7bEk0UcDXt-6MW419I 
Checking to see if there is a valid SPF record. 
Found v=spf1 record for rrh.com: 
v=spf1 include:spf.protection.outlook.com a:mailman1-eqix-sjo.packet8.net a:mailman1-eq.packet8.net -all 
evaluating...
SPF record passed validation test with pySPF (Python SPF librar