diff --git a/backend/src/main/java/com/printcalculator/service/request/CustomQuoteRequestNotificationService.java b/backend/src/main/java/com/printcalculator/service/request/CustomQuoteRequestNotificationService.java
index 84e4eaf..41ecddd 100644
--- a/backend/src/main/java/com/printcalculator/service/request/CustomQuoteRequestNotificationService.java
+++ b/backend/src/main/java/com/printcalculator/service/request/CustomQuoteRequestNotificationService.java
@@ -126,6 +126,9 @@ public class CustomQuoteRequestNotificationService {
     }
 
     private String buildLogoUrl() {
-        return frontendBaseUrl.replaceAll("/+$", "") + "/assets/images/brand-logo-yellow.svg";
+        String baseUrl = frontendBaseUrl == null || frontendBaseUrl.isBlank()
+                ? "http://localhost:4200"
+                : frontendBaseUrl;
+        return baseUrl.replaceAll("/+$", "") + "/assets/images/brand-logo-yellow.svg";
     }
 }
diff --git a/backend/src/test/java/com/printcalculator/service/shop/ShopSitemapServiceTest.java b/backend/src/test/java/com/printcalculator/service/shop/ShopSitemapServiceTest.java
index 988b13e..778a150 100644
--- a/backend/src/test/java/com/printcalculator/service/shop/ShopSitemapServiceTest.java
+++ b/backend/src/test/java/com/printcalculator/service/shop/ShopSitemapServiceTest.java
@@ -92,15 +92,15 @@ class ShopSitemapServiceTest {
         assertTrue(xml.contains("<loc>https://3d-fab.ch/en/shop/accessori</loc>"));
         assertTrue(xml.contains("<loc>https://3d-fab.ch/de/shop/accessori</loc>"));
         assertTrue(xml.contains("<loc>https://3d-fab.ch/fr/shop/accessori</loc>"));
-        assertTrue(xml.contains("hreflang=\"en\" href=\"https://3d-fab.ch/en/shop/accessori\""));
+        assertTrue(xml.contains("hreflang=\"en-CH\" href=\"https://3d-fab.ch/en/shop/accessori\""));
         assertFalse(xml.contains("https://3d-fab.ch/it/shop/bozza"));
 
         assertTrue(xml.contains("<loc>https://3d-fab.ch/it/shop/p/123e4567-supporto-bici</loc>"));
         assertTrue(xml.contains("<loc>https://3d-fab.ch/en/shop/p/123e4567-bike-holder</loc>"));
         assertTrue(xml.contains("<loc>https://3d-fab.ch/de/shop/p/123e4567-fahrrad-halter</loc>"));
         assertTrue(xml.contains("<loc>https://3d-fab.ch/fr/shop/p/123e4567-support-velo</loc>"));
-        assertTrue(xml.contains("hreflang=\"en\" href=\"https://3d-fab.ch/en/shop/p/123e4567-bike-holder\""));
-        assertTrue(xml.contains("hreflang=\"de\" href=\"https://3d-fab.ch/de/shop/p/123e4567-fahrrad-halter\""));
+        assertTrue(xml.contains("hreflang=\"en-CH\" href=\"https://3d-fab.ch/en/shop/p/123e4567-bike-holder\""));
+        assertTrue(xml.contains("hreflang=\"de-CH\" href=\"https://3d-fab.ch/de/shop/p/123e4567-fahrrad-halter\""));
         assertTrue(xml.contains("hreflang=\"x-default\" href=\"https://3d-fab.ch/it/shop/p/123e4567-supporto-bici\""));
         assertTrue(xml.contains("<lastmod>2026-03-11T07:30:00Z</lastmod>"));
         assertFalse(xml.contains("33333333-draft"));