diff --git a/src/service-override/extensions.ts b/src/service-override/extensions.ts
index 72676e32..7368cc28 100644
--- a/src/service-override/extensions.ts
+++ b/src/service-override/extensions.ts
@@ -314,7 +314,7 @@ export default function getServiceOverride(
     workerConfig != null
       ? {
           ...workerConfig,
-          url: changeUrlDomain(workerConfig.url, iframeAlternateDomain ?? globalThis.location?.href ?? import.meta.url)
+          url: changeUrlDomain(new URL(workerConfig.url, globalThis.location?.href ?? import.meta.url), iframeAlternateDomain)
         }
       : undefined
 
diff --git a/src/service-override/tools/url.ts b/src/service-override/tools/url.ts
index ab722b83..c9769f71 100644
--- a/src/service-override/tools/url.ts
+++ b/src/service-override/tools/url.ts
@@ -1,6 +1,6 @@
-export function changeUrlDomain(url: string, domain?: string): string {
+export function changeUrlDomain(url: string | URL, domain?: string): string {
   if (domain == null) {
-    return url
+    return url.toString()
   }
   const _url = new URL(url, domain)
   _url.host = new URL(domain).hostname