diff --git a/app/timetracking/frontend/customers.html b/app/timetracking/frontend/customers.html
index a7a42e6..a5c34e5 100644
--- a/app/timetracking/frontend/customers.html
+++ b/app/timetracking/frontend/customers.html
@@ -928,7 +928,9 @@
             const customerIds = Array.from(selectedCustomers);
             
             try {
-                const response = await fetch('/api/v1/timetracking/customers/bulk-update-rate', {
+                // Use window.location.origin to ensure absolute URL
+                const apiUrl = `${window.location.origin}/api/v1/timetracking/customers/bulk-update-rate`;
+                const response = await fetch(apiUrl, {
                     method: 'POST',
                     headers: {'Content-Type': 'application/json'},
                     body: JSON.stringify({