title: AWS Security group inbound traffic blocked
body: <p>I have an AWS EC2 working instance with a security group allowing <strong>inbound traffic from ports 80, 22 and 443</strong> (HTTP, SSH &amp; HTTPS).
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  Everything was working fine until I opened a few new ports and deleted the rule allowing HTTPS by mistake. Then of course I couldn't access my website. I checked the ports and added 443 again but I'm still having the same problem. The only thing that worked is <strong>allowing ALL traffic</strong> but this is a major security hole. 
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  I have a second AWS instance in another account that has exactly the same security rules and it's working as it should.
  What could possibly be wrong?
  I double checked that it's the <strong>right security group and the rules had been applied</strong>.
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  <p>Ports listening on my server (I'm using Ruby on Rails with nginx)
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  <p>VPC network acl inbound rules:
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  <pre><code>nc -zv &lt;server_ip&gt; 22 and nc -zv &lt;server_ip&gt; 443
  </code></pre>
  
  <p>returns successful on both, when "all traffic" rule is off but still no access</p>