diff --git a/tasks/prepare.yml b/tasks/prepare.yml
index 33a2565f5d382253482bf5c8f4b2daa0265b2e30..914df2de2e4ea0fb21778b478099621e64ba8ad0 100644
--- a/tasks/prepare.yml
+++ b/tasks/prepare.yml
@@ -134,7 +134,7 @@
   delegate_to: "{{hostvars[item.1]['ophinex_cadmin_host']}}"
   with_nested:
     - ['setup_cadmin.sh', 'setup_cadmin.sql']
-    - '{{ groups["webserver-ophinex"] }}'
+    - '{{ groups["webserver-ophinex"]|default([]) }}'
   when: not hostvars[item.1]['ophinex_qa_mode']
 
 - name: "Execute basic setup on all CAdmins"
@@ -142,7 +142,7 @@
   delegate_to: "{{hostvars[item.1]['ophinex_cadmin_host']}}"
   with_nested:
     - ['setup_cadmin.sh']
-    - '{{ groups["webserver-ophinex"] }}'
+    - '{{ groups["webserver-ophinex"]|default([]) }}'
   when: not hostvars[item.1]['ophinex_qa_mode']
 
 - name: "Create files directory for each ophinex instance"
@@ -153,5 +153,5 @@
     mode: '777'
     state: 'directory'
   delegate_to: "{{item}}"
-  with_items: '{{ groups["webserver-ophinex"] }}'
+  with_items: '{{ groups["webserver-ophinex"]|default([]) }}'
   when: not hostvars[item]['ophinex_qa_mode']