diff --git a/src/theme/NavbarItem/NavbarNavLink.tsx b/src/theme/NavbarItem/NavbarNavLink.tsx
index 32c3d81a5b..c6b2fc8d0c 100644
--- a/src/theme/NavbarItem/NavbarNavLink.tsx
+++ b/src/theme/NavbarItem/NavbarNavLink.tsx
@@ -35,7 +35,7 @@ export default function NavbarNavLink({
   const utmParams = useUTMParams();
 
   const appendUtmParams = (url: string): string => {
-    if (!utmParams) {
+    if (!utmParams || !url) {
       return url;
     }