diff --git a/apps/api/src/services/fiel.service.ts b/apps/api/src/services/fiel.service.ts
index 180ff51..99a3100 100644
--- a/apps/api/src/services/fiel.service.ts
+++ b/apps/api/src/services/fiel.service.ts
@@ -44,9 +44,12 @@ export async function uploadFiel(
     const certificate = credential.certificate();
     const rfc = certificate.rfc();
     const serialNumber = certificate.serialNumber().bytes();
-    const validFrom = certificate.validFromDateTime();
-    const validUntil = certificate.validToDateTime();
-    
+    // validFromDateTime() y validToDateTime() retornan strings ISO o objetos DateTime
+    const validFromRaw = certificate.validFromDateTime();
+    const validUntilRaw = certificate.validToDateTime();
+    const validFrom = new Date(String(validFromRaw));
+    const validUntil = new Date(String(validUntilRaw));
+
     // Verificar que no esté vencida
     if (new Date() > validUntil) {
       return {