title: RuntimeError: Could not load the default credentials
body: <p>i've installed <code>google/cloud/translate</code> in my project, the version in the Gemfile.lock is: </p>
  
  <pre><code>google-cloud-translate (2.1.0)
  </code></pre>
  
  <p>With the below code:</p>
  
  <pre><code>require "google/cloud/translate"
  project_id = "&lt;Project ID&gt;" # from my Google Cloud Platform
  translate = Google::Cloud::Translate.new version: :v2, project_id: project_id
  </code></pre>
  
  <p>That is what the <a href="https://cloud.google.com/translate/docs/basic/detecting-language?authuser=1" rel="nofollow noreferrer">documentation</a> says and also what this <a href="https://stackoverflow.com/a/58918041/6796652">answer</a> related suggest (please note that i'm using v2 instead of v3)</p>
  
  <pre><code>RuntimeError: Could not load the default credentials. Browse to
  https://developers.google.com/accounts/docs/application-default-credentials for more information
  </code></pre>
  
  <p>This part returns true:</p>
  
  <pre><code>require "google/cloud/translate"
  </code></pre>
  
  <p><strong>Update</strong>
  I already followed all the steps in: </p>
  
  <p><a href="https://cloud.google.com/docs/authentication/production" rel="nofollow noreferrer">https://cloud.google.com/docs/authentication/production</a></p>
  
  <p>Created a service account, a credential key and set the env variable (on Windows), then I tried testing the credential configuration with the <code>google/cloud/storage</code> example and it's worked fine, but when I tried with: <code>google/cloud/translate</code> gem with </p>
  
  <p><code>translate = Google::Cloud::Translate.new version: :v2, project_id: project_id</code></p>
  
  <p>I still got the same error</p>
  
  <p>What can be the error?
  Thanks in advance for any help.</p>