Empty Shipping Method

When I’m adding a new order in POS page, I try to add shipping to the order as delivery for example. but found the Shipping Method list empty, only appears N/A and 3 empty options and Other.
Here is the HTML code from select box:

<select class="c-select" name="method_id" id="method_id">
<option value="">N/A</option>
<option value="flat_rate"></option>
<option value="free_shipping"></option>
<option value="local_pickup"></option>
<option value="other">Other</option>
</select>

and here is a screenshot for your referance:

Please help me fixing this issue.