Error: The consumer key is already taken

Connected apps include a consumer key that a website or app uses to identify itself to Salesforce. Consumer keys must be unique across the entire Salesforce ecosystem. When you try to deploy the retrieved (and unchanged) source file associated with the connected app to a new org, the deploy fails due to duplicate consumer keys.

You have a few options to work around this problem.

• Remove the connected app source file from your project before you deploy your source to the new org. As a result, the connected app isn’t created. The connected app source file is named something like force-app/main/default/connectedApps/MyConnApp.connectedApp-meta.xml.
• Update the file for the connected app and change the value of the <consumerKey> element to a unique value. Here’s a snippet of a sample connected app file that shows the <consumerKey> element.
  <?xml version="1.0" encoding="UTF-8"?>
  <ConnectedApp xmlns="http://soap.sforce.com/2006/04/metadata">
      <contactEmail>john@doecompany.com</contactEmail>
      <contactPhone>5556789</contactPhone>
      <label>MyConnApp</label>
      <oauthConfig>
          <callbackUrl>http://localhost:1717/OauthRedirect</callbackUrl>
          <consumerKey>3MVG9PG9sFc71i9n55UWbx2</consumerKey>
          <isAdminApproved>false</isAdminApproved>
  ...