title: PHP mail sender authentication warning
body: <p>I am sending mail from my hosting server through this PHP code :</p>
  
  <pre><code>mail("myemail@gmail.com", "Subject: Verify Eg Net Solution ID", $randStr , "From: Egnetsolution@gmail.com" );
  </code></pre>
  
  <p>In <code>myemail@gmail.com</code> the email is send but there is a warning that is saying :</p>
  
  <pre><code>"This message may not have been sent by: Egnetsolution@gmail.com  Learn more  Report phishing"
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/sAoXy.jpg" alt="enter image description here">
  What I have to do in my hosting domain server. I will really appreciate you if you can give me a solution.</p>