Quick fix

go/templates/quotes/index.html

@@ -371,13 +371,17 @@ document.getElementById('modalConfirmBtn').addEventListener('click', async funct
         const formData = new FormData(currentForm);
         formData.append('reminder_type', currentReminderType);
         
+        // Convert FormData to URLSearchParams for proper form encoding
+        const params = new URLSearchParams(formData);
+        
         try {
             const response = await fetch('/go/quotes/send-reminder', {
                 method: 'POST',
                 headers: {
-                    'X-Requested-With': 'XMLHttpRequest'
+                    'X-Requested-With': 'XMLHttpRequest',
+                    'Content-Type': 'application/x-www-form-urlencoded'
                 },
-                body: formData
+                body: params
             });
             
             if (response.ok) {