diff --git a/validate-my-dns.py b/validate-my-dns.py
index de5bbc9..8a3f81c 100755
--- a/validate-my-dns.py
+++ b/validate-my-dns.py
@@ -17,6 +17,7 @@ try:
     import dns.message
     import dns.resolver
     import dns.rdatatype
+    import dns.rcode
 except ImportError:
     print()
     print("CRITICAL: this script requires the 'dnspython' libary, please install it using `python3 -m pip install dnspython`")
@@ -76,7 +77,9 @@ def get_domain_by_mntner(mntner):
                 if line.startswith("nserver"):
                     _tmp = _parse_nserver(line)
                     if _tmp == "break": break
-                    if _tmp[0] in domains[domain_name]["nserver"]:
+                    if _tmp[1] == None:
+                        domains[domain_name]["nserver"][_tmp[0]] = None
+                    elif _tmp[0] in domains[domain_name]["nserver"]:
                         domains[domain_name]["nserver"][_tmp[0]].append(_tmp[1])
                     else:
                         domains[domain_name]["nserver"][_tmp[0]
@@ -197,7 +200,7 @@ def get_dnskey(domain_name, nserver):
     if response[0].rcode() != 0:
         # HANDLE QUERY FAILED (SERVER ERROR OR NO DNSKEY RECORD)
         print(
-            f"WARN: query for a DNSKEY on {domain_name} failed on {nserver}, returncode: {response[0].rcode()}")
+            f"WARN: query for a DNSKEY on {domain_name} failed on {nserver}, returncode: {dns.rcode.to_text(response[0].rcode())}")
         errors += 1
         return False
     return [dnskey.to_text().split("IN DNSKEY ")[1] for dnskey in response[0].answer]