title: Heroku Redis Add-On Error error:1408F10B:SSL routines:ssl3_get_record:wrong version number
body: <p>After upgrading my Heroku Redis add-on to v6.2.3 from v4, Heroku papertrail logs display this error: <code>Error accepting a client connection: error:1408F10B:SSL routines:ssl3_get_record:wrong version number</code>  <br /> I am connecting to Redis using NodeJs and the <code>bull</code> npm package (<a href="https://www.npmjs.com/package/bull" rel="nofollow noreferrer">https://www.npmjs.com/package/bull</a>). I found similar questions related to this error, along with Heroku documentation, and based on that I have set my <code>bull</code> redis options to the following: <br /></p>
  <pre><code>redis: {
      host: redisURL.hostname,
      port: Number(redisURL.port),
      password: redisURL.password,
      tls: {
        rejectUnauthorized: false,
      },
    },
  </code></pre>
  <p>Note the <code>tls</code> parameter. I have set it to Heroku's recommendations here: <a href="https://devcenter.heroku.com/articles/heroku-redis#connecting-in-node-js" rel="nofollow noreferrer">https://devcenter.heroku.com/articles/heroku-redis#connecting-in-node-js</a> <br /> <br /> After getting stuck for a while, I attempted to simply comment out any client code that connects to Redis, delete the add-on, and re-provision the add-on. I expected to see no redis logs in papertrail when I did this, but I still see the same error, even when no code that connects to redis is being run... This leads me to believe maybe it's a setting on the actual Redis add-on instance, rather than an issue with my code, but I am at a loss.</p>
  <p><strong>Updates:</strong></p>
  <p>I logged into the redis:cli and did some investigation. <code>client list</code> reveals 2 client connections. 1 is the instance of the redis:cli I am running in my terminal, and another is the a client with a flag that means &quot;the client is a replica node connection to this instance&quot; (see <a href="https://redis.io/commands/client-list" rel="nofollow noreferrer">https://redis.io/commands/client-list</a>). What is interesting is the error that is being logged in papertrail shows the file descriptor for the client connection that is having the SSL error <code>fd=12</code>, while the 2 clients shown in <code>client list</code> have the file descriptors <code>fd=10</code> and <code>fd=11</code>. So there must be another client connection with <code>fd=12</code> that isn't appearing in <code>client list</code> command causing the error shown above.</p>