UIWebView Delegate Method shouldStartLoadWithRequest: is not getting called - ios

Question

I am creating an iOS App. In which, There is a webview, having url, which has authentication challenge.
How I am dealing with it, In my app first page is asking for login credential from user. Then pass this credential to next viewController where webView exists. After that I load a request in webView in viewDidLoad(). It fires it's delegate method shouldStartLoadWithRequest:, Where I setup a NSUrlRequest to pass credential into authentication challenge. This whole scenario is working fine every time until authentication challenge gets failed.
When Authentication challenge gets failed I take the user in previous login View and make user to enter login credential again. This time I go to next viewController where webView is existed, with credential and load request in viewDidLoad, shouldStartLoadWithRequest doesn't get called. I have tried everything like clearing the session, clearing the cache, but still no success.
Here is the code for setup WebView Request
- (void)viewDidLoad
{
[super viewDidLoad];
[_webviewclass loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:contentURL]]];
_webviewclass.delegate = self;
_webviewclass.dataDetectorTypes = UIDataDetectorTypeLink | UIDataDetectorTypePhoneNumber;
}
And this is delegate method
this one is getting called after authentication failed
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
UrlRequest = request;
NSURL * localurl = [request URL];
if (![[localurl absoluteString] isEqualToString:#"about:blank"])
{
InDownloading = YES;
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
NSLog(#" connection to remove warning : %#",connection);
[self WaitForConnectionDownload];
return YES;
}
return NO;
}
Please guys help me out.
Thank you