add defauts + asseet-vars

assert-vars.yml

@@ -1,8 +1,4 @@
 - name: verify if vars are defined and not empty
   assert:
     that:
-      - "{{ item }} is defined and {{ item }}|length > 0"
-    fail_msg: "'{{ item }}' is not defined or empty"
-    success_msg: "'{{ item }} ' is defined"
-  with_items:
     - mail_domain

defaults/main.yml

@@ -1,6 +1,6 @@
 ---
 #postfix
-#mail_domain: gmotech.dyndns.org
+mail_domain: gmotech.dyndns.org
 #mail_relay_host: smtpauths.bluewin.ch
 #mail_relay_host: smtp.gmail.com
 # DNS