title: SendGrid smtp not sending to Yahoo, AOL, or Verizon.net but sends to Gmail?
body: <p><em>(Disclaimer I'm fairly new to development in general and this is my first StackOverflow post all and any feedback is greatly appreciated.)</em></p>
  <p>I'm posting here because I'm on a free SendGrid account and their support team has yet to get back to respond and it's been over a week and I'm dying to solve this issue.</p>
  <p>Currently, I'm using Sendgrid as an SMTP and recently my emails have stopped sending to the following esp Yahoo, AOL, and Verizon.net but emails send to Gmail just fine.</p>
  <p>Because emails still send to Gmail I used &quot;Email Header Analyzer&quot; via mxtoolbox.com to review and meet the recommendations provided. Which I have implemented on. (See screenshot)</p>
  <p>The only thing not checked off is the &quot;DKIM Authenticated&quot; in which it's my understanding that when you verify the domain you're using to send emails with SendGrid takes care of that for you.</p>
  <p>It's not the email function itself because it sends just fine to Gmail.</p>
  <p>My question is has anyone else experienced this issue? If so what was the fix you did that made it work?</p>
  <p><strong>Screenshot of my email header analyzer results:</strong></p>
  <p><img src="https://i.stack.imgur.com/MAdk5.png" alt="Screenshot of my email header analyzer results" /></p>