diff --git a/src/site/config.ts b/src/site/config.ts
index f1bfea88..43f3861a 100644
--- a/src/site/config.ts
+++ b/src/site/config.ts
@@ -10,9 +10,9 @@ const VERCEL_URL = VERCEL_BRANCH_URL && VERCEL_BRANCH
   ? `${VERCEL_BRANCH_URL.split(`-git-${VERCEL_BRANCH}-`)[0]}.vercel.app`
   : undefined;
 
-const SITE_DOMAIN =
-  process.env.NEXT_PUBLIC_SITE_DOMAIN ||
-  VERCEL_URL;
+const SITE_DOMAIN = process.env.NEXT_PUBLIC_SITE_DOMAIN
+  ? process.env.NEXT_PUBLIC_SITE_DOMAIN.toLowerCase()
+  : VERCEL_URL;
 
 const SITE_DOMAIN_SHORT = shortenUrl(SITE_DOMAIN);