diff --git a/tasks/local-certificate.yml b/tasks/local-certificate.yml
index 924a64d..1be5bd2 100644
--- a/tasks/local-certificate.yml
+++ b/tasks/local-certificate.yml
@@ -24,7 +24,7 @@
     privatekey_path: "{{ certificate_privatekey_path if certificate_privatekey_path is defined else None }}"
     privatekey_size: "{{ certificate_privatekey_size if certificate_privatekey_size is defined else None }}"
     common_name: "{{ certificate_common_name }}"
-    alt_name: "{{ certificate_alt_name if certificate_alt_name is defined else None }}"
+    alt_name: "{{ certificate_alt_name | default([]) }}"
     before_expired_hours: "{{ certificate_before_expired_hours if certificate_before_expired_hours is defined else 72 }}"
     force: "{{ certificate_force if certificate_force is defined else false }}"
   register: certout
diff --git a/tasks/remote-certificate.yml b/tasks/remote-certificate.yml
index 9a3e6d7..b0f9af4 100644
--- a/tasks/remote-certificate.yml
+++ b/tasks/remote-certificate.yml
@@ -14,7 +14,7 @@
     privatekey_path: "{{ certificate_privatekey_path if certificate_privatekey_path is defined else None }}"
     privatekey_size: "{{ certificate_privatekey_size if certificate_privatekey_size is defined else None }}"
     common_name: "{{ certificate_common_name }}"
-    alt_name: "{{ certificate_alt_name if certificate_alt_name is defined else None }}"
+    alt_name: "{{ certificate_alt_name | default([]) }}"
     before_expired_hours: "{{ certificate_before_expired_hours if certificate_before_expired_hours is defined else None }}"
     force: "{{ certificate_force if certificate_force is defined else false }}"
   register: certout