diff --git a/ansible/library/machinectl.py b/ansible/library/machinectl.py
index 58e9994..946f3fa 100644
--- a/ansible/library/machinectl.py
+++ b/ansible/library/machinectl.py
@@ -154,7 +154,7 @@ def run_module():
     module_args = dict(
         state=dict(type='str', required=True),
         machines=dict(type='list', required=True),
-        tls_machine=dict(type='str', required=True),
+        tls_machine=dict(type='str', required=False),
     )
 
     # seed the result dict in the object
@@ -184,10 +184,10 @@ def run_module():
     # manipulate or modify the state as needed (this is going to be the
     # part where your module will do what it needs to do)
     machines = module.params['machines']
-    tls_machine = module.params['tls_machine']
+    tls_machine = module.params.get('tls_machine')
     if module.params['state'] == 'stopped':
-        if tls_machine and tls_machine not in machines:
-            machines.append(tls_machine)
+        if tls_machine and tls_machine in machines:
+            machines.remove(tls_machine)
         bus = SystemBus()
         result['changed'], errors = stop(bus, machines)
         if errors: