diff --git a/apps/st/app/api/proxy/[...url]/route.ts b/apps/st/app/api/proxy/[...url]/route.ts
index 261d6b259..8d2ce62dc 100644
--- a/apps/st/app/api/proxy/[...url]/route.ts
+++ b/apps/st/app/api/proxy/[...url]/route.ts
@@ -5,6 +5,7 @@ import {
     ACCESS_TOKEN,
     AUTH_USER_ID,
     CLAIM_NAME,
+    COOKIE_DOMAIN,
     REFRESH_TOKEN,
     SERVER_API_URL,
     SITE_ID,
@@ -75,6 +76,7 @@ async function handler(
                 cookieStore.set(REFRESH_TOKEN, refreshToken, {
                     httpOnly: true,
                     sameSite: "lax",
+                    domain: COOKIE_DOMAIN,
                     path: "/",
                 });
             }