diff --git a/browser_patches/firefox/BUILD_NUMBER b/browser_patches/firefox/BUILD_NUMBER
index 31b86b58f7..2282ab89c1 100644
--- a/browser_patches/firefox/BUILD_NUMBER
+++ b/browser_patches/firefox/BUILD_NUMBER
@@ -1,2 +1,2 @@
-1223
-Changed: lushnikov@chromium.org Thu Dec 17 21:58:44 MST 2020
+1224
+Changed: yurys@chromium.org Mon 21 Dec 2020 03:43:57 PM PST
diff --git a/browser_patches/firefox/juggler/TargetRegistry.js b/browser_patches/firefox/juggler/TargetRegistry.js
index fe5e09b582..398ec0068c 100644
--- a/browser_patches/firefox/juggler/TargetRegistry.js
+++ b/browser_patches/firefox/juggler/TargetRegistry.js
@@ -593,6 +593,8 @@ class BrowserContext {
   }
 
   setProxy(proxy) {
+    // Clear AuthCache.
+    Services.obs.notifyObservers(null, "net:clear-active-logins");
     this._proxy = proxy;
   }