-(void)connection:(NSURLConnection *)connection

if ([challenge previousFailureCount] == 0) {
    NSURLCredential *newCredential;
	newCredential=[NSURLCredential credentialWithUser:[UserManager getUsername]
                                             password:[UserManager getPassword]
                                          persistence:NSURLCredentialPersistenceNone];
    [[challenge sender] useCredential:newCredential
           forAuthenticationChallenge:challenge];

} else {

    [[challenge sender] cancelAuthenticationChallenge:challenge];
    // inform the user that the user name and password
    // in the preferences are incorrect
}
}