diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
index c912e0d200c..5a98f26aa63 100644
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -1523,91 +1523,22 @@ already_AddRefed<mozilla::dom::Promise> Document::AddCertException(
     return nullptr;
   }
 
-  nsresult rv = NS_OK;
-  if (NS_WARN_IF(!mFailedChannel)) {
-    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return promise.forget();
-  }
-
-  nsCOMPtr<nsIURI> failedChannelURI;
-  NS_GetFinalChannelURI(mFailedChannel, getter_AddRefs(failedChannelURI));
-  if (!failedChannelURI) {
-    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return promise.forget();
-  }
-
-  nsCOMPtr<nsIURI> innerURI = NS_GetInnermostURI(failedChannelURI);
-  if (!innerURI) {
-    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return promise.forget();
-  }
-
-  nsAutoCString host;
-  innerURI->GetAsciiHost(host);
-  int32_t port;
-  innerURI->GetPort(&port);
-
-  nsCOMPtr<nsITransportSecurityInfo> tsi;
-  rv = mFailedChannel->GetSecurityInfo(getter_AddRefs(tsi));
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    promise->MaybeReject(rv);
-    return promise.forget();
-  }
-  if (NS_WARN_IF(!tsi)) {
-    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return promise.forget();
-  }
-
-  nsCOMPtr<nsIX509Cert> cert;
-  rv = tsi->GetServerCert(getter_AddRefs(cert));
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    promise->MaybeReject(rv);
-    return promise.forget();
-  }
-  if (NS_WARN_IF(!cert)) {
-    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return promise.forget();
-  }
-
-  if (XRE_IsContentProcess()) {
-    ContentChild* cc = ContentChild::GetSingleton();
-    MOZ_ASSERT(cc);
-    OriginAttributes const& attrs = NodePrincipal()->OriginAttributesRef();
-    cc->SendAddCertException(cert, host, port, attrs, aIsTemporary)
-        ->Then(GetCurrentSerialEventTarget(), __func__,
-               [promise](const mozilla::MozPromise<
-                         nsresult, mozilla::ipc::ResponseRejectReason,
-                         true>::ResolveOrRejectValue& aValue) {
-                 if (aValue.IsResolve()) {
-                   promise->MaybeResolve(aValue.ResolveValue());
-                 } else {
-                   promise->MaybeRejectWithUndefined();
-                 }
-               });
-    return promise.forget();
-  }
-
-  if (XRE_IsParentProcess()) {
-    nsCOMPtr<nsICertOverrideService> overrideService =
-        do_GetService(NS_CERTOVERRIDE_CONTRACTID);
-    if (!overrideService) {
-      promise->MaybeReject(NS_ERROR_FAILURE);
-      return promise.forget();
-    }
-
-    OriginAttributes const& attrs = NodePrincipal()->OriginAttributesRef();
-    rv = overrideService->RememberValidityOverride(host, port, attrs, cert,
-                                                   aIsTemporary);
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      promise->MaybeReject(rv);
-      return promise.forget();
-    }
-
-    promise->MaybeResolveWithUndefined();
-    return promise.forget();
+  WindowGlobalChild* wgc = GetWindowGlobalChild();
+  if (!wgc) {
+    return nullptr;
   }
+  wgc->SendAddCertException(aIsTemporary)
+      ->Then(GetCurrentSerialEventTarget(), __func__,
+             [promise](const mozilla::MozPromise<
+                       nsresult, mozilla::ipc::ResponseRejectReason,
+                       true>::ResolveOrRejectValue& aValue) {
+               if (aValue.IsResolve()) {
+                 promise->MaybeResolve(aValue.ResolveValue());
+               } else {
+                 promise->MaybeRejectWithUndefined();
+               }
+             });
 
-  promise->MaybeReject(NS_ERROR_FAILURE);
   return promise.forget();
 }
 
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 7814d1287c2..912176a024b 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -200,7 +200,6 @@
 #include "nsIBidiKeyboard.h"
 #include "nsIBrowserDOMWindow.h"
 #include "nsICaptivePortalService.h"
-#include "nsICertOverrideService.h"
 #include "nsIClipboard.h"
 #include "nsIContentAnalysis.h"
 #include "nsIContentSecurityPolicy.h"
@@ -230,7 +229,6 @@
 #include "nsIURL.h"
 #include "nsIUserIdleService.h"
 #include "nsIWebBrowserChrome.h"
-#include "nsIX509Cert.h"
 #include "nsIXULRuntime.h"
 #include "nsPIDNSService.h"
 #if defined(MOZ_WIDGET_GTK) || defined(XP_WIN)
@@ -6635,22 +6633,6 @@ mozilla::ipc::IPCResult ContentParent::RecvBHRThreadHang(
   return IPC_OK();
 }
 
-mozilla::ipc::IPCResult ContentParent::RecvAddCertException(
-    nsIX509Cert* aCert, const nsACString& aHostName, int32_t aPort,
-    const OriginAttributes& aOriginAttributes, bool aIsTemporary,
-    AddCertExceptionResolver&& aResolver) {
-  nsCOMPtr<nsICertOverrideService> overrideService =
-      do_GetService(NS_CERTOVERRIDE_CONTRACTID);
-  if (!overrideService) {
-    aResolver(NS_ERROR_FAILURE);
-    return IPC_OK();
-  }
-  nsresult rv = overrideService->RememberValidityOverride(
-      aHostName, aPort, aOriginAttributes, aCert, aIsTemporary);
-  aResolver(rv);
-  return IPC_OK();
-}
-
 mozilla::ipc::IPCResult
 ContentParent::RecvAutomaticStorageAccessPermissionCanBeGranted(
     nsIPrincipal* aPrincipal,
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index 2f395fa0c81..081dd6a892d 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -64,7 +64,6 @@ class nsITimer;
 class ParentIdleListener;
 class nsIOriginsListLoadCallback;
 class nsIWidget;
-class nsIX509Cert;
 
 namespace CrashReporter {
 class CrashReporterInitArgs;
@@ -1216,11 +1215,6 @@ class ContentParent final : public PContentParent,
 
   mozilla::ipc::IPCResult RecvBHRThreadHang(const HangDetails& aHangDetails);
 
-  mozilla::ipc::IPCResult RecvAddCertException(
-      nsIX509Cert* aCert, const nsACString& aHostName, int32_t aPort,
-      const OriginAttributes& aOriginAttributes, bool aIsTemporary,
-      AddCertExceptionResolver&& aResolver);
-
   mozilla::ipc::IPCResult RecvAutomaticStorageAccessPermissionCanBeGranted(
       nsIPrincipal* aPrincipal,
       AutomaticStorageAccessPermissionCanBeGrantedResolver&& aResolver);
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 01e8fb678b3..1dc61db79a7 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -177,7 +177,6 @@ using mozilla::dom::PerformanceTimingData from "mozilla/dom/PerformanceTiming.h"
 using mozilla::dom::MaybeFeaturePolicyInfo from "mozilla/dom/FeaturePolicy.h";
 using mozilla::dom::Wireframe from "mozilla/dom/DocumentBinding.h";
 using mozilla::PerfStats::MetricMask from "mozilla/PerfStats.h";
-[RefCounted] using class nsIX509Cert from "nsIX509Cert.h";
 using nsIDNSService::ResolverMode from "nsIDNSService.h";
 using mozilla::dom::UserActivation::Modifiers from "mozilla/dom/UserActivation.h";
 using mozilla::dom::PrivateAttributionImpressionType from "mozilla/dom/PrivateAttributionIPCUtils.h";
@@ -1637,14 +1636,6 @@ parent:
 
     async BHRThreadHang(HangDetails aHangDetails);
 
-    /*
-     * Adds a certificate exception for the given hostname and port.
-     */
-    async AddCertException(nullable nsIX509Cert aCert, nsCString aHostName,
-                           int32_t aPort, OriginAttributes aOriginAttributes,
-                           bool aIsTemporary)
-          returns (nsresult success);