diff --git a/lib/nntp/tiny/session.py b/lib/nntp/tiny/session.py
index 259593c..f424b0e 100644
--- a/lib/nntp/tiny/session.py
+++ b/lib/nntp/tiny/session.py
@@ -710,7 +710,7 @@ class Session():
         if value is None or value == '':
             return False
 
-        names      = map(lambda s: s.lower(), value)
+        names      = map(lambda s: s.lower(), self.RE_NEWSGROUPS_SPLIT.split(value))
         newsgroups = list()
 
         for name in names:
@@ -725,7 +725,7 @@ class Session():
         message.message_id_assign()
 
         if not message.validate():
-            return self.respond(ResponseCode.NNTP_POST_FAILED)
+            return False
 
         self.db.add(message)