Getting error using Facebook XMPP library for chat application on iPhone

I am using the XMPP framework to add Facebook chat functionality to my iPhone application. I am however, getting the following error while testing:

<failure xmlns="urn:ietf:params:xml:ns:xmpp-sasl"><not-authorized/></failure>

Full error message here:

2011-08-09 12:17:49.781 FacebookStaticTest[4217:207] RECV: <challenge xmlns="urn:ietf:params:xml:ns:xmpp-sasl">cmVhbG09ImNoYXQuZmFjZWJvb2suY29tIixub25jZT0iRDg4QkREMTNFMTcwRjEwOUVGMDI2OTkwRjExMzYyMTYiLHFvcD0iYXV0aCIsY2hhcnNldD11dGYtOCxhbGdvcml0aG09bWQ1LXNlc3M=</challenge>
2011-08-09 12:17:49.781 FacebookStaticTest[4217:207] decoded challenge: realm="chat.facebook.com",nonce="D88BDD13E170F109EF026990F1136216",qop="auth",charset=utf-8,algorithm=md5-开发者_如何学JAVAsess
2011-08-09 12:17:50.072 FacebookStaticTest[4217:207] RECV: <failure xmlns="urn:ietf:params:xml:ns:xmpp-sasl"><not-authorized/></failure>
2011-08-09 12:17:50.073 FacebookStaticTest[4217:207] RECV: <failure xmlns="urn:ietf:params:xml:ns:xmpp-sasl"><not-authorized/></failure>

I have already read Facebook chat document and made the following changes:

• Set the Application Type to Native app and Save Changes.
• Select the Advanced tab.
• Under Migrations, change Disable Deprecated Auth Methods from Enabled to Disabled and Save Changes.

I also tried creating a new application ... but got the same error ...

Please help, thanks in advance.