title: Network Error when use axios in React Native
body: <p>This is long-standing problem for me and I can't find solution at all.</p>
  
  <p>Within my react native project(react-native-cli), I send request to server using axios package.
  But when I'm testing with my android phone, it gives [Error: Network Error].
  With emulator, it's okay.</p>
  
  <p>I'm sure this is not back-end problem because I've tested with several servers.
  And I also used fetch instead but got same error.</p>
  
  <p>Here is version information.</p>
  
  <pre><code>"axios": "^0.19.0",
  "react": "16.9.0",
  "react-native": "0.61.5",
  </code></pre>
  
  <p>Sometimes, it's working on android phone too.
  This problem is biggest mystery and I suffered for a long time.</p>
  
  <p>Somebody who experienced this issue, please alive me.
  Thank you for careful reading.</p>
  
  <p><em>Sometimes, it's not working even with android emulator. But after deleted original emulator and created new emulator, it's working.</em></p>
  
  <pre><code>const serverUrl = "https://server.com";
  axios.post(serverUrl + "/api/candidates/login", {
              "email": this.state.email ,
              "password": this.state.password
          }, {
              headers: {
                  'Content-Type': 'application/json'
              }
          }).then((response) =&gt; {
                  console.log(response.data);
          }).catch((error) =&gt; {
                  console.log(error);
          })
  </code></pre>