CAP - Custom Error Handling

For some reason, my code was not able to map custom error msg ORDER_EXCEEDS_STOCK and its corresponding placeholders (see below)

<code>// i18n/messages_en.properties

<code>ORDER_EXCEEDS_STOCK=The order of {0} books exceeds the stock by {1}

to rejection handler below

<code>// srv/catalog-service.js

.....

req.reject(400, 'ORDER_EXCEEDS_STOCK', [val1, val2])

Below is the output that I am getting; as you can see I'm only getting back the name of my custom error msg instead of its value.

// Error msg

http://docs.oasis-open.org/odata/ns/metadata">

<code>400</code>
<message>ORDER_EXCEEDS_STOCK</message>
</error>

Thanks in advance!