diff --git a/server/middleware/multi-tenant-auth.js b/server/middleware/multi-tenant-auth.js
index a03f747..dc1c857 100644
--- a/server/middleware/multi-tenant-auth.js
+++ b/server/middleware/multi-tenant-auth.js
@@ -90,9 +90,15 @@ class MultiTenantAuth {
     // Method 5: Subdomain (tenant.yourapp.com)
     const hostname = req.hostname || req.headers.host || '';
     if (hostname && !hostname.startsWith('localhost')) {
-      const subdomain = hostname.split('.')[0];
-      if (subdomain && subdomain !== 'www' && subdomain !== 'api' && !subdomain.includes(':')) {
-        return subdomain;
+      const hostParts = hostname.split('.');
+      // Only treat as subdomain if there are at least 2 parts (subdomain.domain.com)
+      // and the first part is not a common root domain
+      if (hostParts.length >= 3) {
+        const subdomain = hostParts[0];
+        if (subdomain && subdomain !== 'www' && subdomain !== 'api' && !subdomain.includes(':')) {
+          console.log('🏢 Tenant from subdomain:', subdomain);
+          return subdomain;
+        }
       }
     }