Problem with simple app to consume REST api

Hi everyone!!

I’m trying to develop an application that uses the REST api provided by LoRa App Server.
In more detail, a very simple one, in HTML with jQuery.
I understood and made it work the REST api by the web page (LoRaAppServerURL/api) using the jwt authentication.
And if I tried with Firefox Poster plugin, it also works.
The thing is that, with the HTML with jQuery I can not make it work. I’m trying a simple GET, but when setting in the header the ‘Grpc-Metadata-Authorization’ in the request, it changes the GET for an OPTIONS request.
Trying to solve this, I have read that is a CORS matter. And some people recommend to add something like that to the REST api server:
Header always set Access-Control-Allow-Origin: “*”
Header always set Access-Control-Allow-Methods “POST, GET, PUT, DELETE, OPTIONS”
Header always set Access-Control-Allow-Headers “origin, x-requested-with, content-type”

But if so, that would mean editing the core of the LoRa App Server.

Is there another solution? How can I solve this issue?

Thanks in advance.