diff --git a/remote/webdriver-bidi/modules/root/input.sys.mjs b/remote/webdriver-bidi/modules/root/input.sys.mjs
index a84f2aa6d46e..6a58d7611df2 100644
--- a/remote/webdriver-bidi/modules/root/input.sys.mjs
+++ b/remote/webdriver-bidi/modules/root/input.sys.mjs
@@ -27,6 +27,13 @@ class InputModule extends Module {
     );
 
     const context = lazy.TabManager.getBrowsingContextById(contextId);
+    if (!context) {
+      throw new lazy.error.NoSuchFrameError(
+        `Browsing context with id ${contextId} not found`
+      );
+    }
+
+    // Bug 1821460: Fetch top-level browsing context.
 
     await this.messageHandler.forwardCommand({
       moduleName: "input",