遇到iOS网址打不开的情况

看到很多网上说设置清除缓存
self.request = [NSURLRequest requestWithURL:[NSURL URLWithString:htmlString] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:5.0];

貌似这个我也没用，我出现的bug是版本跟新后网址在iphone手机上打不开，新建过一个工程后是可以打开的，一开始认为是UIWebView的bug,最后一气之下卸载重新App Store上安装居然可以打开网址了。。。。。
最后后台大佬告诉我说iOS是需要做一个登录的验证什么的，具体搞后端的肯定明白

开始以为是未加入证书验证，然并不是。

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge; {
    NSLog(@"WebController Got auth challange via NSURLConnection");
    
    if ([challenge previousFailureCount] == 0) {
        _authenticated = YES;
        NSURLCredential *credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
        [challenge.sender useCredential:credential forAuthenticationChallenge:challenge];
        
    } else {
        [[challenge sender] cancelAuthenticationChallenge:challenge];
        
    }
    
}
// We use this method is to accept an untrusted site which unfortunately we need to do, as our PVM servers are self signed.
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace {
    return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}
#pragma mark - NSURLConnectionDataDelegate

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
    NSLog(@"WebController received response via NSURLConnection");
    // remake a webview call now that authentication has passed ok.
    _authenticated = YES;
    [self.webView loadRequest:_request];
    // Cancel the URL connection otherwise we double up (webview + url connection, same url = no good!)
    [_urlConnection cancel];
    
}

我真是什么bug都能碰见啊