diff --git a/modoboa/admin/constants.py b/modoboa/admin/constants.py
index ce41092be..45704b6d7 100644
--- a/modoboa/admin/constants.py
+++ b/modoboa/admin/constants.py
@@ -21,7 +21,6 @@ DNSBL_PROVIDERS = [
     "dnsbl-3.uceprotect.net",
     "dnsbl.cyberlogic.net",
     "dnsbl.inps.de",
-    "dnsbl.njabl.org",
     "dnsbl.sorbs.net",
     "drone.abuse.ch",
     "duinv.aupads.org",
diff --git a/modoboa/admin/management/commands/subcommands/_mx.py b/modoboa/admin/management/commands/subcommands/_mx.py
index 8c1a8e7d2..09fe918fe 100644
--- a/modoboa/admin/management/commands/subcommands/_mx.py
+++ b/modoboa/admin/management/commands/subcommands/_mx.py
@@ -114,7 +114,7 @@ class CheckMXRecords(BaseCommand):
         results = {}
         for mx in mx_list:
             reverse = ".".join(reversed(mx.address.split(".")))
-            pattern = "{}.{}".format(reverse, provider)
+            pattern = "{}.{}.".format(reverse, provider)
             try:
                 results[mx] = socket.gethostbyname(pattern)
             except socket.gaierror: