UIWebview成为空白页面

Question

在我的应用程序中，我使用网络身份验证登录我的应用程序，如下图所示：

现在我遇到了一个问题，有时我登录然后注销并再次登录，uiwebview显示一个空白的白页如下：

我不知道发生了什么。有人得到这样的问题吗？我该如何解决？ 这是代码：

- (void)loadWebView {

NSString *urlString = @"https://api.ewings.vn/dialog/SdkWebView/login/?";
urlString = [urlString stringByAppendingString:[NSString stringWithFormat:@"redirect_uri=sh%@://",[Soha sharedInstance].gameId]];
NSDictionary *defaultParam = [SHRequest addMoreParametersForSOAPAPIsFromParam:nil WithOldAPI:NO];
for (NSString *key in defaultParam.allKeys) {
    urlString = [urlString stringByAppendingString:[NSString stringWithFormat:@"&%@=%@", key, [defaultParam objectForKey:key]]];
}
[self.loginWebview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:urlString]]];
}

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{

if([request.description containsString:@"access_token"]){

    NSString* accessToken = [request.description componentsSeparatedByString:@"access_token="][1];
    accessToken = [accessToken componentsSeparatedByString:@"&"][0];

    NSString *decoded = (__bridge_transfer NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(NULL, (CFStringRef)accessToken, CFSTR(""), kCFStringEncodingUTF8);

    [Soha sharedInstance].gameAccessToken = decoded;
    [[SHLoginModal sharedModal] getUserInfoWithBlock:^(NSDictionary *userInfo, NSError *error) {
        if (accessToken) {
            [self loginSuccessfully];
            self.loginWebview = nil;
        }

    }];

}

NSLog(@"request des : %@",[request URL]);
return YES;
}

-(void)webViewDidStartLoad:(UIWebView *)webView{
self.backButton.enabled = (self.loginWebview.canGoBack);
}

-(void)webViewDidFinishLoad:(UIWebView *)webView{
self.backButton.enabled = (self.loginWebview.canGoBack);
}

- (void)viewDidLoad {
[super viewDidLoad];
self.loginWebview.delegate = self;

self.navigationView.backgroundColor = SHColorFromHEX(0x167AC6);
[self.navigationTitle setText:@"Login"];
[self.backButton addTarget:self.loginWebview
                    action:@selector(goBack)
          forControlEvents:UIControlEventTouchDown];

[self loadWebView];
}