Error loading url behind a proxy

[marco-1988]

Greetings

I am trying to load a url in the webview that is configured behind a reverse proxy, that if I open it in the browser with url launcher everything is ok, instead with the webview it does not load it and gives this error when I try to load it:

`======== Exception caught by services library ======================================================
The following _CastError was thrown during a platform message callback:
Null check operator used on a null value

When the exception was thrown, this was the stack:
#0 _WebViewXState.build.onWebResourceError (package:webviewx/src/view/impl/mobile.dart:167:34)
#1 _PlatformCallbacksHandler.onWebResourceError (package:webview_flutter/src/webview.dart:490:34)
#2 WebKitWebViewPlatformController.navigationDelegate.. (package:webview_flutter_wkwebview/src/web_kit_webview_widget.dart:170:50)
#3 WKNavigationDelegateFlutterApiImpl.didFailProvisionalNavigation (package:webview_flutter_wkwebview/src/web_kit/web_kit_api_impls.dart:822:15)
#4 WKNavigationDelegateFlutterApi.setup. (package:webview_flutter_wkwebview/src/common/web_kit.pigeon.dart:1511:15)
#5 BasicMessageChannel.setMessageHandler. (package:flutter/src/services/platform_channel.dart:197:49)
#6 _DefaultBinaryMessenger.setMessageHandler. (package:flutter/src/services/binding.dart:387:35)
#7 _invoke2. (dart:ui/hooks.dart:189:15)
#11 _invoke2 (dart:ui/hooks.dart:188:10)
#12 _ChannelCallbackRecord.invoke (dart:ui/channel_buffers.dart:42:5)
#13 _Channel.push (dart:ui/channel_buffers.dart:132:31)
#14 ChannelBuffers.push (dart:ui/channel_buffers.dart:329:17)
#15 PlatformDispatcher._dispatchPlatformMessage (dart:ui/platform_dispatcher.dart:599:22)
#16 _dispatchPlatformMessage (dart:ui/hooks.dart:89:31)
(elided 3 frames from dart:async)
====================================================================================================`

Can you help me? Thank you

[marco-1988]

I have found that on the web (release and debug) and Android (I have only tried debugging) it works fine. On iOS in debug it does not work and returns the error I indicated. I have not tried if in release it has the same problem.

For iOS do I have to do something extra to make it work? The error I have only with this link which is behind the proxy, but on the Web and Android with this link I have no problem. Can you help me? Thank you