diff --git a/widgets/webview/webpage.cpp b/widgets/webview/webpage.cpp
index e8985ad..fd0fdac 100644
--- a/widgets/webview/webpage.cpp
+++ b/widgets/webview/webpage.cpp
@@ -18,7 +18,6 @@
 #include <QWebEngineCertificateError>
 #include <QWebEngineSettings>
 #include <QWebEngineView>
-#include <QtWebEngineWidgetsVersion>
 #elif defined(SYNCTHINGWIDGETS_USE_WEBKIT)
 #include <QNetworkRequest>
 #include <QSslError>
@@ -47,6 +46,9 @@ WebPage::WebPage(WebViewDialog *dlg, SYNCTHINGWIDGETS_WEB_VIEW *view)
 {
 #ifdef SYNCTHINGWIDGETS_USE_WEBENGINE
     settings()->setAttribute(QWebEngineSettings::JavascriptCanOpenWindows, true);
+#if (QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+    connect(this, &WebPage::certificateError, this, &WebPage::handleCertificateError);
+#endif
     connect(
         this, &WebPage::authenticationRequired, this, static_cast<void (WebPage::*)(const QUrl &, QAuthenticator *)>(&WebPage::supplyCredentials));
 #else // SYNCTHINGWIDGETS_USE_WEBKIT
@@ -101,14 +103,16 @@ SYNCTHINGWIDGETS_WEB_PAGE *WebPage::createWindow(SYNCTHINGWIDGETS_WEB_PAGE::WebW
 }
 
 #ifdef SYNCTHINGWIDGETS_USE_WEBENGINE
-/*!
- * \brief Accepts self-signed certificates used by the Syncthing GUI as configured.
- * \remarks Before Qt 5.14 any self-signed certificates are accepted.
- */
-bool WebPage::certificateError(const QWebEngineCertificateError &certificateError)
+bool WebPage::canIgnoreCertificateError(const QWebEngineCertificateError &certificateError) const
 {
     // never ignore errors other than CertificateCommonNameInvalid and CertificateAuthorityInvalid
-    switch (certificateError.error()) {
+    switch (certificateError
+#if (QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+                .type()
+#else
+                .error()
+#endif
+    ) {
     case QWebEngineCertificateError::CertificateCommonNameInvalid:
     case QWebEngineCertificateError::CertificateAuthorityInvalid:
         break;
@@ -148,6 +152,31 @@ bool WebPage::certificateError(const QWebEngineCertificateError &certificateErro
     return true;
 }
 
+/*!
+ * \brief Accepts self-signed certificates used by the Syncthing GUI as configured.
+ * \remarks
+ * - Before Qt 5.14 any self-signed certificates are accepted.
+ * - The const_cast used in the Qt 6 version is most likely wrong and not how to the API is
+ *   supposed to be used. The [documentation](https://doc-snapshots.qt.io/qt6-dev/qwebenginepage.html#certificateError)
+ *   mentions one is able to ignore certificate errors but does not state how.
+ */
+#if (QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+void WebPage::handleCertificateError(const QWebEngineCertificateError &certificateError)
+{
+    auto &error = const_cast<QWebEngineCertificateError &>(certificateError);
+    if (canIgnoreCertificateError(certificateError)) {
+        error.acceptCertificate();
+    } else {
+        error.rejectCertificate();
+    }
+}
+#else
+bool WebPage::certificateError(const QWebEngineCertificateError &certificateError)
+{
+    return canIgnoreCertificateError(certificateError);
+}
+#endif
+
 /*!
  * \brief Accepts navigation requests only on the same page.
  */
diff --git a/widgets/webview/webpage.h b/widgets/webview/webpage.h
index daba687..75a2594 100644
--- a/widgets/webview/webpage.h
+++ b/widgets/webview/webpage.h
@@ -30,11 +30,13 @@ public:
 protected:
     SYNCTHINGWIDGETS_WEB_PAGE *createWindow(WebWindowType type) override;
 #ifdef SYNCTHINGWIDGETS_USE_WEBENGINE
-    bool certificateError(const QWebEngineCertificateError &certificateError) override;
+#if (QTWEBENGINEWIDGETS_VERSION < QT_VERSION_CHECK(6, 0, 0))
+    bool certificateError(const QWebEngineCertificateError &certificateError) override; // signal in Qt >= 6
+#endif
     bool acceptNavigationRequest(const QUrl &url, NavigationType type, bool isMainFrame) override;
     void javaScriptConsoleMessage(
         QWebEnginePage::JavaScriptConsoleMessageLevel level, const QString &message, int lineNumber, const QString &sourceID) override;
-#else
+#else // SYNCTHINGWIDGETS_USE_WEBKIT
     bool acceptNavigationRequest(QWebFrame *frame, const QNetworkRequest &request, NavigationType type) override;
     void javaScriptConsoleMessage(const QString &message, int lineNumber, const QString &sourceID) override;
 #endif
@@ -44,7 +46,11 @@ private Q_SLOTS:
     void supplyCredentials(const QUrl &requestUrl, QAuthenticator *authenticator);
     void supplyCredentials(QNetworkReply *reply, QAuthenticator *authenticator);
     void supplyCredentials(QAuthenticator *authenticator);
-#ifdef SYNCTHINGWIDGETS_USE_WEBKIT
+#ifdef SYNCTHINGWIDGETS_USE_WEBENGINE
+#if (QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+    void handleCertificateError(const QWebEngineCertificateError &certificateError);
+#endif
+#else // SYNCTHINGWIDGETS_USE_WEBKIT
     void handleSslErrors(QNetworkReply *, const QList<QSslError> &errors);
 #endif
     void injectJavaScripts(bool ok);
@@ -53,6 +59,9 @@ private Q_SLOTS:
     void showFolderPathSelection(const QString &defaultDir);
 
 private:
+#ifdef SYNCTHINGWIDGETS_USE_WEBENGINE
+    bool canIgnoreCertificateError(const QWebEngineCertificateError &certificateError) const;
+#endif
     static bool handleNavigationRequest(const QUrl &currentUrl, const QUrl &url);
 
     WebViewDialog *m_dlg;
diff --git a/widgets/webview/webviewincludes.h b/widgets/webview/webviewincludes.h
index 626c3f7..a0b4ce7 100644
--- a/widgets/webview/webviewincludes.h
+++ b/widgets/webview/webviewincludes.h
@@ -9,6 +9,7 @@
 #if defined(SYNCTHINGWIDGETS_USE_WEBENGINE)
 # include <QWebEngineView>
 # include <QWebEnginePage>
+# include <QtWebEngineWidgetsVersion>
 #elif defined(SYNCTHINGWIDGETS_USE_WEBKIT)
 # include <QWebView>
 # include <QWebPage>