added login check and explanation for config file
diff --git a/cvp_checks/global_config.yaml b/cvp_checks/global_config.yaml
index 74dbbb5..927a232 100644
--- a/cvp_checks/global_config.yaml
+++ b/cvp_checks/global_config.yaml
@@ -1,5 +1,15 @@
 ---
-# MANDATORY: Credentials for Salt master
+# MANDATORY: Credentials for Salt Master
+# SALT_URL should consist of url and port.
+# For example: http://10.0.0.1:6969
+# 6969 - default Salt Master port to listen
+# Can be found on cfg* node using
+# "salt-call pillar.get _param:salt_master_host"
+# and "salt-call pillar.get _param:salt_master_port"
+# SALT_USERNAME by default: salt
+# It can be verified with "salt-call shadow.info salt"
+# SALT_PASSWORD you can find on cfg* node using
+# "grep -r salt_api_password /srv/salt/reclass/classes"
 SALT_URL: <salt_url>
 SALT_USERNAME: <salt_usr>
 SALT_PASSWORD: <salt_pwd>
@@ -23,4 +33,4 @@
 # this test may skip specific node (use fqdn)
 test_ntp_sync:
   { #"skipped_nodes": [""],
-    "time_deviation": 30}
+    "time_deviation": 1}
diff --git a/cvp_checks/utils/__init__.py b/cvp_checks/utils/__init__.py
index c05a281..3c485c5 100644
--- a/cvp_checks/utils/__init__.py
+++ b/cvp_checks/utils/__init__.py
@@ -18,10 +18,13 @@
         login_request = requests.post(os.path.join(config['SALT_URL'],
                                                    'login'),
                                       headers=headers, data=login_payload)
-        request = requests.post(config['SALT_URL'], headers=headers,
-                                data=accept_key_payload,
-                                cookies=login_request.cookies)
-        return request.json()['return'][0]
+        if login_request.ok:
+            request = requests.post(config['SALT_URL'], headers=headers,
+                                    data=accept_key_payload,
+                                    cookies=login_request.cookies)
+            return request.json()['return'][0]
+        else:
+            raise EnvironmentError("401 Not authorized.")
 
 
 def init_salt_client():