diff --git a/src/demos/chips/routes.js b/src/demos/chips/routes.js
index 799d7d2..6d7cabd 100644
--- a/src/demos/chips/routes.js
+++ b/src/demos/chips/routes.js
@@ -25,7 +25,7 @@ router.get( '/analytics.js', ( req, res ) => {
 
 		// Store the analytics ID in a cookie
 		res.cookie( 'analyticsId', analyticsId, {
-			Domain: res.locals.domainC,
+			Domain: `.${res.locals.domainC}`,
 			maxAge: 30 * 24 * 60 * 60 * 1000, // 30 days
 			httpOnly: true,
 			sameSite: "none",
diff --git a/src/scenarios/analytics/routes.js b/src/scenarios/analytics/routes.js
index 3e69dcd..cc64dfb 100644
--- a/src/scenarios/analytics/routes.js
+++ b/src/scenarios/analytics/routes.js
@@ -34,7 +34,7 @@ router.get('/analytics.js', (req, res) => {
 
         // Store the user name in a cookie
         res.cookie('userName', userName, {
-            Domain: res.locals.domainC,
+            Domain: `.${res.locals.domainC}`,
             maxAge: 30 * 24 * 60 * 60 * 1000, // 30 days
             httpOnly: true,
             sameSite: "none",
diff --git a/src/scenarios/payment-gateway/routes.js b/src/scenarios/payment-gateway/routes.js
index b454de5..69224ab 100644
--- a/src/scenarios/payment-gateway/routes.js
+++ b/src/scenarios/payment-gateway/routes.js
@@ -19,7 +19,7 @@ router.get( '/payment-form', ( req, res ) => {
 		res.cookie( 'session_id', 'some_random_session_id', {
 			maxAge: 900000,
 			httpOnly: true,
-			domain: res.locals.domainC,
+			domain: `.${res.locals.domainC}`,
 			sameSite: 'none',
 			secure: true
 		} );
diff --git a/src/scenarios/personalization/routes.js b/src/scenarios/personalization/routes.js
index 8710137..c541a30 100644
--- a/src/scenarios/personalization/routes.js
+++ b/src/scenarios/personalization/routes.js
@@ -22,7 +22,7 @@ router.post( '/set-personalization', ( req, res ) => {
     }
     
     res.cookie('theme', theme, {
-        domain: res.locals.domainC,
+        domain: `.${res.locals.domainC}`,
         maxAge: 30 * 24 * 60 * 60 * 1000, // 30 days
         httpOnly: true,
         sameSite: "none",
diff --git a/src/scenarios/single-sign-on/routes.js b/src/scenarios/single-sign-on/routes.js
index 77ac535..8e26190 100644
--- a/src/scenarios/single-sign-on/routes.js
+++ b/src/scenarios/single-sign-on/routes.js
@@ -46,7 +46,7 @@ router.get('/sign-in', (req, res) => {
 router.post('/validate', (req, res) => {
 	const email = req.body.email;
 	if (email) {
-		res.cookie('email', email, { maxAge: 900000, httpOnly: true, domain: res.locals.domainC, sameSite: "none", secure: true });
+		res.cookie('email', email, { maxAge: 900000, httpOnly: true, domain: `.${res.locals.domainC}`, sameSite: "none", secure: true });
 		res.render(path.join(__dirname, 'postmessage'), { email: email });
 	} else {
 		res.status(400).send('Email validation failed');