title: Magento 2 - Custom Shipping Carrier and methods not showing in frontend
body: <p>I am currently trying to create a new shipping carrier that will get its rates and methods through xml online. It seems that everything is working fine since i was able to debug that the method collectCarrierRates in module-shipping\Model\Shipping.php is actually appending all the methods and their rates but they are not showing in the checkout/cart page.</p>
  
  <p>If i leave the zipcode empty i get the carrier title and under it stating "This shipping method is not available. Please specify the zip code." but if i add the zip code the carrier title disappears and no methods are shown. </p>
  
  <p>I would really appreciate any info on how to further debug this problem. Since i am not able to follow where the rates are going after being generated by this function.</p>
  
  <p>Thanks</p>