diff --git a/src/sumo/wrapper/_auth_provider.py b/src/sumo/wrapper/_auth_provider.py
index 1b45597..dc7a4c3 100644
--- a/src/sumo/wrapper/_auth_provider.py
+++ b/src/sumo/wrapper/_auth_provider.py
@@ -92,6 +92,11 @@ def store_shared_access_key_for_case(self, case_uuid, token):
             f.write(token)
         protect_token_cache(self._resource_id, ".sharedkey", case_uuid)
 
+    def has_case_token(self, case_uuid):
+        return os.path.exists(
+            get_token_path(self._resource_id, ".sharedkey", case_uuid)
+        )
+
     pass
 
 
diff --git a/src/sumo/wrapper/sumo_client.py b/src/sumo/wrapper/sumo_client.py
index b5eddaa..383b198 100644
--- a/src/sumo/wrapper/sumo_client.py
+++ b/src/sumo/wrapper/sumo_client.py
@@ -424,13 +424,16 @@ def create_shared_access_key_for_case(self, case_uuid):
     def client_for_case(self, case_uuid):
         """Instantiate and return new SumoClient for accessing the
         case identified by *case_uuid*."""
-        return SumoClient(
-            env=self.env,
-            verbosity=self._verbosity,
-            retry_strategy=self._retry_strategy,
-            timeout=self._timeout,
-            case_uuid=case_uuid,
-        )
+        if self.auth.has_case_token(case_uuid):
+            return SumoClient(
+                env=self.env,
+                verbosity=self._verbosity,
+                retry_strategy=self._retry_strategy,
+                timeout=self._timeout,
+                case_uuid=case_uuid,
+            )
+        else:
+            return self
 
     @raise_for_status_async
     async def get_async(self, path: str, params: dict = None):