I'm sorry - I've seen a bunch of posts on this subject but I still cant seem to get anywhere 
I have an existing WCF REST web service that is currently being used for an iPad application and I am trying to figure out how to return the JSON response in Sencha Touch 2. I have tried MANY different approaches, but here is my current one:
Code:
Ext.Ajax.request({
url: 'https://ADDRESSTOSERVICE/user.svc/user/name/' + vals.loginUsername + '/password/' + vals.loginPassword,
headers: {
'Authorization': 'Basic ' + Base64.encode(vals.loginUsername + ':' + vals.loginPassword),
"Content-type": "application/json; charset=utf-8",
},
params:{
username: vals.loginUsername,
password: vals.loginPassword
},
success: function(form, result){
console.log("SUCCESS");
},
failure: function(form, result){
console.log("FAILED");
}
});
In CHROME I am getting :Failed to load resource: Resource failed to load followed by the url
If I click on the error URL, my expected JSON response is displayed in the browser window. This is intended to go cross-domain. I can successfully call this service with Fiddler and get the expected response.
I dont know if this is enough info to help- if not please let me know and I can supply more. Thanks!