diff --git a/api/kiwi_vpn_api/easyrsa.py b/api/kiwi_vpn_api/easyrsa.py
index 3f464c2..0b79386 100644
--- a/api/kiwi_vpn_api/easyrsa.py
+++ b/api/kiwi_vpn_api/easyrsa.py
@@ -252,12 +252,15 @@ class EasyRSA:
     def issue(
         self,
         cert_type: CertificateType = CertificateType.client,
-        dn: DistinguishedName = DistinguishedName.build(),
+        dn: DistinguishedName | None = None,
     ) -> crypto.X509 | None:
         """
         Issue a client or server certificate
         """
 
+        if dn is None:
+            dn = DistinguishedName.build()
+
         if not (cert_type is CertificateType.client
                 or cert_type is CertificateType.server):
             return None