diff --git a/roles/mailserver/tasks/main.yml b/roles/mailserver/tasks/main.yml
index 2d2496b..518f641 100644
--- a/roles/mailserver/tasks/main.yml
+++ b/roles/mailserver/tasks/main.yml
@@ -8,17 +8,23 @@
   - block:
     - include_tasks: install_postfix.yml
     - include_tasks: configure_postfix.yml
-    when: postfix == true
+    when: 
+      - postfix is defined
+      - postfix == true
 
   - block:
     - include_tasks: install_dovecot.yml
     - include_tasks: configure_dovecot.yml
-    when: dovecot == true
+    when:
+      - dovecot is defined
+      - dovecot == true
 
   - block:
     - include_tasks: install_fetchmail.yml
     - include_tasks: configure_fetchmail.yml
-    when: fetchmail == true
+    when:
+      - fetchmail is defined
+      - fetchmail == true
 
   rescue:
     - set_fact: task_failed=true
\ No newline at end of file