iOS Device not allowing navigation

Hello all,
I’m developing for iOS for the first time and I’m with trouble when calling my API using a post request and trying to open a browser.
The post request is odd, in device it work if I use my DNS (it’s a self signed certificate) but doesn’t work when I use the direct IP address. But both ways work when I test using “ionic serve -l”.
When trying the direct IP address the request return the status 0, here is my code:

var ip = "";
var link = 'https://'+ip+':9090/api/ping';
var request = new XMLHttpRequest();"POST", link, true);
request.timeout = 2000;
request.onreadystatechange = function (oEvent) {
   if (request.readyState === 4) {

I have already put this in my iconfig.xml, but nothing changed:

<allow-navigation href="*" />

When I try to open a navigation tab, wich contains a “howto” on our website, in “ionic serve -l” it works fine, but in iOS device it simply don’t do nothing:

this.iab.create('', '_system', 'location=yes');

I tryed with (it worked in android) but then I installed the plugin InAppBrowser, but no success.

Thanks in advance.