diff --git a/tasks/main.yml b/tasks/main.yml
index a929037..e60ada9 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -6,7 +6,7 @@
 
 - fail:
     msg: 'Invalid `common__iptables__state`: {{ common__iptables__state }}'
-  when: (common__iptables__state != null) and
+  when: (common__iptables__state != None) and
         (common__iptables__state != 'purge') and
         (common__iptables__state != 'remove') and
         (common__iptables__state != 'install')
@@ -20,7 +20,7 @@
 
 - fail:
     msg: 'Invalid `common__certbot__state`: {{ common__certbot__state }}'
-  when: (common__certbot__state != null) and
+  when: (common__certbot__state != None) and
         (common__certbot__state != 'purge') and
         (common__certbot__state != 'remove') and
         (common__certbot__state != 'install')
@@ -34,7 +34,7 @@
 
 - fail:
     msg: 'Invalid `common__apache__state`: {{ common__apache__state }}'
-  when: (common__apache__state != null) and
+  when: (common__apache__state != None) and
         (common__apache__state != 'purge') and
         (common__apache__state != 'remove') and
         (common__apache__state != 'install')
@@ -48,7 +48,7 @@
 
 - fail:
     msg: 'Invalid `common__nginx__state`: {{ common__nginx__state }}'
-  when: (common__nginx__state != null) and
+  when: (common__nginx__state != None) and
         (common__nginx__state != 'purge') and
         (common__nginx__state != 'remove') and
         (common__nginx__state != 'install')