diff --git a/check_mk_web_api/__init__.py b/check_mk_web_api/__init__.py
index 2341508..9f89a7a 100644
--- a/check_mk_web_api/__init__.py
+++ b/check_mk_web_api/__init__.py
@@ -149,7 +149,7 @@ def make_request(self, action, query_params=None, data=None):
 
         body = response.read().decode()
 
-        if body.startswith('Authentication error:'):
+        if re.match('(^Authentication error:|^Permission denied: Invalid automation secret)', body):
             raise CheckMkWebApiAuthenticationException(body)
 
         if 'output_format' in query_params and query_params['output_format'] == 'python':