title: PayTm All-in-one Sdk - after successful payment getting error like Webpage not available - callback url error
body: <p>full error message is :
  <strong>The webpage at <a href="https://merchant.com/callback" rel="nofollow noreferrer">https://merchant.com/callback</a> could not be loaded because : net::ERR_CONNECTION_TIME_OUT</strong></p>
  <p><a href="https://i.stack.imgur.com/aUBVJ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aUBVJ.jpg" alt="enter image description here" /></a></p>
  <p>my code for initiate paytm and get same error in app invocation :</p>
  <pre><code> private void startPayTMCall(InitiateAPIResponse apiResponse, PaytmInitRequestBody paytmInitRequestBody) {
          String orderIdString = paytmInitRequestBody.getOrderId();
          String MID = getString(R.string.MID);
          String amount = String.valueOf(paytmInitRequestBody.getAmount());
  
  /*
          On completion of transaction, Paytm payment gateway will send the response on this URL. This can be a static response URL as mentioned below:
          Staging Environment: &quot;https://securegw-stage.paytm.in/theia/paytmCallback?ORDER_ID=&lt;order_id&gt;&quot;
          Production Environment: &quot;https://securegw.paytm.in/theia/paytmCallback?ORDER_ID=&lt;order_id&gt;&quot;*/
          // for test mode use it
          // String host = &quot;https://securegw-stage.paytm.in/&quot;;
          // for production mode use it
          String host = &quot;https://securegw.paytm.in/&quot;;
          String callBackUrl = host + &quot;theia/paytmCallback?ORDER_ID=&quot; + orderIdString;
  
  
          PaytmOrder order = new PaytmOrder(orderIdString, MID, apiResponse.getBody().getTxnToken(), amount, callBackUrl);
  
                              TransactionManager transactionManager = new TransactionManager(order, new PaytmPaymentTransactionCallback() {
                      @Override
                      public void onTransactionResponse(Bundle bundle) {
                          Toast.makeText(getApplicationContext(), &quot;Payment Transaction response &quot; + bundle.toString(), Toast.LENGTH_LONG).show();
                      }
  
                      @Override
                      public void networkNotAvailable() {
                          Toast.makeText(MainActivity.this, &quot;networkNotAvailable&quot;, Toast.LENGTH_SHORT).show();
                      }
  
                      @Override
                      public void onErrorProceed(String s) {
                          Toast.makeText(MainActivity.this, &quot;onErrorProceed &quot;+s, Toast.LENGTH_SHORT).show();
                      }
  
                      @Override
                      public void clientAuthenticationFailed(String s) {
                          Toast.makeText(MainActivity.this, &quot;clientAuthenticationFailed : &quot;+s, Toast.LENGTH_SHORT).show();
                      }
  
                      @Override
                      public void someUIErrorOccurred(String s) {
                          Toast.makeText(MainActivity.this, &quot;someUIErrorOccurred : &quot;+s, Toast.LENGTH_SHORT).show();
  
                      }
  
                      @Override
                      public void onErrorLoadingWebPage(int i, String s, String s1) {
                          Toast.makeText(MainActivity.this, &quot;onErrorLoadingWebPage : &quot;+s+&quot; : &quot;+s1, Toast.LENGTH_SHORT).show();
  
                      }
  
                      @Override
                      public void onBackPressedCancelTransaction() {
                          Toast.makeText(MainActivity.this, &quot;onBackPressedCancelTransaction : &quot;, Toast.LENGTH_SHORT).show();
  
                      }
  
                      @Override
                      public void onTransactionCancel(String s, Bundle bundle) {
                          Toast.makeText(MainActivity.this, &quot;onTransactionCancel : &quot;+s, Toast.LENGTH_SHORT).show();
  
                      }
                  });
  
  
          transactionManager.setAppInvokeEnabled(false);
          transactionManager.setEnableAssist(true);
          transactionManager.startTransaction(this, REQ_CODE_ORDER);
  
      }
  </code></pre>
  <p>i think there is problem in callback url tht could be worng, but i follow paytm official All in one SDK documentation. <strong><a href="https://developer.paytm.com/docs/all-in-one-sdk/" rel="nofollow noreferrer">https://developer.paytm.com/docs/all-in-one-sdk/</a></strong></p>