Recently, there's a bunch of networking issues, failing us some WPTs
For example, http://wpt.live/svg/linking/reftests/href-image-element.html fails with

Error: An unexpected network error occurred (status: 200 OK)

While attempting to load PNG. I have added a verification

diff --git a/Libraries/LibWeb/SVG/SVGImageElement.cpp b/Libraries/LibWeb/SVG/SVGImageElement.cpp
index a3f2d6d674..78d3f769d3 100644
--- a/Libraries/LibWeb/SVG/SVGImageElement.cpp
+++ b/Libraries/LibWeb/SVG/SVGImageElement.cpp
@@ -156,6 +156,7 @@ void SVGImageElement::fetch_the_document(URL::URL const& url)
         [this] {
             m_load_event_delayer.clear();
             auto image_data = m_resource_request->image_data();
+            VERIFY(image_data);
             if (image_data->is_animated() && image_data->frame_count() > 1) {
                 m_current_frame_index = 0;
                 m_animation_timer->set_interval(image_data->frame_duration(0));

that fails as

VERIFICATION FAILED: image_data at /Users/pavel/Develop/ladybird/Libraries/LibWeb/SVG/SVGImageElement.cpp:159
0   liblagom-ak.0.0.0.dylib             0x0000000100feb280 ak_trap + 56
1   liblagom-ak.0.0.0.dylib             0x0000000100feb594 ak_assertion_failed + 0
2   liblagom-web.0.0.0.dylib            0x0000000102e06d08 AK::Function<void ()>::CallableWrapper<Web::SVG::SVGImageElement::fetch_the_document(URL::URL const&)::$_0>::call() + 312
3   liblagom-web.0.0.0.dylib            0x00000001028b8d64 AK::Function<void (AK::Span<unsigned char>)>::operator()(AK::Span<unsigned char>) const + 76
4   liblagom-web.0.0.0.dylib            0x0000000102c9d328 AK::Function<AK::ErrorOr<void, AK::Error> (Web::Platform::DecodedImage&)>::CallableWrapper<Web::HTML::SharedResourceRequest::handle_successful_fetch(URL::URL const&, AK::StringView, AK::Detail::ByteBuffer<32ul>)::$_0>::call(Web::Platform::DecodedImage&) + 544
5   liblagom-webview.0.0.0.dylib        0x0000000100abc610 AK::Function<AK::ErrorOr<void, AK::Error> (Web::Platform::DecodedImage&)>::operator()(Web::Platform::DecodedImage&) const + 76
6   liblagom-webview.0.0.0.dylib        0x0000000100ac3950 Core::Promise<Web::Platform::DecodedImage, AK::Error>::resolve(Web::Platform::DecodedImage&&) + 544
7   liblagom-webview.0.0.0.dylib        0x0000000100ac342c AK::Function<AK::ErrorOr<void, AK::Error> (ImageDecoderClient::DecodedImage&)>::CallableWrapper<WebView::ImageCodecPlugin::decode_image(AK::Span<unsigned char const>, AK::Function<AK::ErrorOr<void, AK::Error> (Web::Platform::DecodedImage&)>, AK::Function<void (AK::Error&)>)::$_0>::call(ImageDecoderClient::DecodedImage&) + 204
8   liblagom-imagedecoderclient.0.0.0.d 0x0000000100957fe4 AK::Function<AK::ErrorOr<void, AK::Error> (ImageDecoderClient::DecodedImage&)>::operator()(ImageDecoderClient::DecodedImage&) const + 76
9   liblagom-imagedecoderclient.0.0.0.d 0x0000000100955694 Core::Promise<ImageDecoderClient::DecodedImage, AK::Error>::resolve(ImageDecoderClient::DecodedImage&&) + 544
10  liblagom-imagedecoderclient.0.0.0.d 0x00000001009550c0 ImageDecoderClient::Client::did_decode_image(long long, bool, unsigned int, Gfx::BitmapSequence const&, AK::Vector<unsigned int, 0ul> const&, Gfx::Point<float>, Gfx::ColorSpace const&) + 336
11  liblagom-imagedecoderclient.0.0.0.d 0x0000000100955ae0 ImageDecoderClientStub::handle(IPC::Message const&) + 104
12  liblagom-ipc.0.0.0.dylib            0x0000000100a23e7c IPC::ConnectionBase::handle_messages() + 224
13  liblagom-ipc.0.0.0.dylib            0x0000000100a253c8 AK::Function<void ()>::CallableWrapper<IPC::ConnectionBase::ConnectionBase(IPC::Stub&, IPC::TransportSocket, unsigned int)::$_1>::call() + 92
14  liblagom-core.0.0.0.dylib           0x0000000100cd8024 AK::Function<void (AK::Error&)>::operator()(AK::Error&) const + 76
15  liblagom-core.0.0.0.dylib           0x0000000100cd8024 AK::Function<void (AK::Error&)>::operator()(AK::Error&) const + 76
16  liblagom-core.0.0.0.dylib           0x0000000100cd7564 Core::EventReceiver::dispatch_event(Core::Event&, Core::EventReceiver*) + 112
17  liblagom-core.0.0.0.dylib           0x0000000100ce8078 Core::ThreadEventQueue::process() + 400
18  liblagom-core.0.0.0.dylib           0x0000000100cd523c Core::EventLoop::spin_until(AK::Function<bool ()>) + 116
19  liblagom-web.0.0.0.dylib            0x0000000102dc1edc Web::Platform::EventLoopPluginSerenity::spin_until(GC::Root<GC::Function<bool ()>>) + 116
20  liblagom-web.0.0.0.dylib            0x0000000102b9c4b8 Web::HTML::EventLoop::spin_until(GC::Ref<GC::Function<bool ()>>) + 360
21  liblagom-web.0.0.0.dylib            0x0000000102c55b94 Web::HTML::HTMLParser::the_end(GC::Ref<Web::DOM::Document>, GC::Ptr<Web::HTML::HTMLParser>) + 992
22  liblagom-web.0.0.0.dylib            0x0000000102c556b8 Web::HTML::HTMLParser::run(URL::URL const&, Web::HTML::HTMLTokenizer::StopAtInsertionPoint) + 244
23  liblagom-web.0.0.0.dylib            0x0000000102aaa160 AK::Function<void ()>::CallableWrapper<Web::load_html_document(Web::HTML::NavigationParams const&)::$_0::operator()(AK::Detail::ByteBuffer<32ul>) const::'lambda'()>::call() + 128
24  liblagom-web.0.0.0.dylib            0x00000001028b8d64 AK::Function<void (AK::Span<unsigned char>)>::operator()(AK::Span<unsigned char>) const + 76
25  liblagom-core.0.0.0.dylib           0x0000000100cd8024 AK::Function<void (AK::Error&)>::operator()(AK::Error&) const + 76
26  liblagom-core.0.0.0.dylib           0x0000000100ce8030 Core::ThreadEventQueue::process() + 328
27  liblagom-core.0.0.0.dylib           0x0000000100cebda4 Core::EventLoopImplementationUnix::exec() + 44
28  liblagom-core.0.0.0.dylib           0x0000000100cd50dc Core::EventLoop::exec() + 72
29  WebContent                          0x000000010073daec serenity_main(Main::Arguments) + 4292
30  WebContent                          0x00000001007da7cc main + 196

Returning null pointer on successful data retrieval doesn't look good, and failed data retrieval is supposed to run on_fail callback, that never happens.
As discussed yesterday at #testing on Discord, the problem of the same kind occurs on https://wpt.live//css/css-images/object-fit-scale-down-png-001e.html , that prevented @InvalidUsernameException from running this WPT on wpt.live
The problem is reproducible at least on two machines, and it seems to sometimes happen on WPT runner as well