Web requests fail in custom visual when using Internet Explorer

[Master_T]

Hello everyone

In my custom visual, I have this piece of code that does an ajax call to our backend server, using jQuey:

$.ajax({
url: "https://localhost:9099/Auth/Ping",
method: "GET",
xhrFields: {
withCredentials: true
},
success: function(){ console.log("success");},
error: function(){ console.log("error");}
});

Normally, this code works without problems even in Internet Explorer, I did a test and I can confirm that, in a normal webpage, this works perfectly in IE.

However, when I put it inside a PowerBI custom visual, the code fails and I get this error on the javascript console:

https://i.imgur.com/OiUf9hs.png 

I've checked the error code, but it's not much use, it indicates a generic "network error". Note that, again, on any other web page this works without issues in IE.

The even wierder thing is, if I check the network tab, the request seems to have completed succesfully and without errors:

https://i.imgur.com/gKnXMNe.png 

So the call is actually going through and returning correctly (code 200), but for some reason IE still considers it failed and stops the script.

Anyone has any idea of what is going on here? To summarize:

-This problem only occours when running this code in a PowerBI custom visual, using this code on a normal webpage doesn't have any issues
-This problem only occurs on Internet Explorer, other browsers behave correctly (what a surprise...)
-This is not a CORS issue, the server is correctly configured for CORS (and also, as I've already stated: this works on other browsers without errors)

Any help would be appreciated.

EDIT: just to rule it out, I tried using a normal XMLHttpRequest instead of jQuery's "ajax" method, but I get the same exact error.

[Master_T]

I've created a minimal example of this error for testing, if anyone is willing to take a look at it:

https://github.com/tarockx/PbiCustomVisualIeNetworkError