diff --git a/.circleci/config.yml b/.circleci/config.yml
index e7df668..f78282d 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -2,7 +2,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: 218546966473.dkr.ecr.us-east-1.amazonaws.com/circle-ci:tap-tester
+      - image: 218546966473.dkr.ecr.us-east-1.amazonaws.com/circle-ci:stitch-tap-tester
     steps:
       - checkout
       - run:
@@ -16,12 +16,12 @@ jobs:
           name: 'Pylint'
           command: |
             source ~/.virtualenvs/tap-marketo/bin/activate
-            pylint tap_marketo -d C,R
+            pylint tap_marketo -d C,R,W
       - run:
           name: 'JSON Validator'
           command: |
             source /usr/local/share/virtualenvs/tap-tester/bin/activate
-            stitch-validate-json ~/.virtualenvs/tap-marketo/lib/python3.5/site-packages/tap_marketo/schemas/*.json
+            stitch-validate-json tap_marketo/schemas/*.json
       - run:
           name: 'Unit Tests'
           command: |
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69b1b5f..f9a8632 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## 2.5.1
+  * Fixed Validation Error for `max_daily_calls` [#84](https://github.com/singer-io/tap-marketo/pull/84)
+
 ## 2.5.0
   * Add campaignId field to activities streams [#82](https://github.com/singer-io/tap-marketo/pull/82)
 
diff --git a/setup.py b/setup.py
index 6914127..1870f19 100644
--- a/setup.py
+++ b/setup.py
@@ -3,7 +3,7 @@
 from setuptools import setup
 
 setup(name='tap-marketo',
-      version='2.5.0',
+      version='2.5.1',
       description='Singer.io tap for extracting data from the Marketo API',
       author='Stitch',
       url='http://singer.io',
diff --git a/tap_marketo/client.py b/tap_marketo/client.py
index 49f268f..de0291d 100644
--- a/tap_marketo/client.py
+++ b/tap_marketo/client.py
@@ -26,7 +26,7 @@
 # Marketo limits REST requests to 50000 per day with a rate limit of 100
 # calls per 20 seconds.
 # http://developers.marketo.com/rest-api/
-MAX_DAILY_CALLS = int(50000 * 0.8)
+MAX_DAILY_CALLS = 50000 * 0.8
 RATE_LIMIT_CALLS = 100
 RATE_LIMIT_SECONDS = 20
 
@@ -80,7 +80,7 @@ def raise_for_rate_limit(data):
 class Client:
     # pylint: disable=unused-argument
     def __init__(self, endpoint, client_id, client_secret,
-                 max_daily_calls=MAX_DAILY_CALLS,
+                 max_daily_calls=None,
                  user_agent=DEFAULT_USER_AGENT,
                  job_timeout=JOB_TIMEOUT,
                  poll_interval=POLL_INTERVAL,
@@ -89,7 +89,14 @@ def __init__(self, endpoint, client_id, client_secret,
         self.domain = extract_domain(endpoint)
         self.client_id = client_id
         self.client_secret = client_secret
-        self.max_daily_calls = int(max_daily_calls)
+        try:
+            self.max_daily_calls = int(max_daily_calls or MAX_DAILY_CALLS)
+            if self.max_daily_calls <= 1:
+                raise ValueError("Limit Cannot be Negative or Zero")
+        except (ValueError, TypeError) as err:
+            singer.log_critical(f"Invalid Value passed for max_daily_calls: {max_daily_calls}")
+            raise err
+
         self.user_agent = user_agent
         self.job_timeout = job_timeout
         self.poll_interval = poll_interval
diff --git a/tests/test_client_max_api_limit.py b/tests/test_client_max_api_limit.py
new file mode 100644
index 0000000..51ac50d
--- /dev/null
+++ b/tests/test_client_max_api_limit.py
@@ -0,0 +1,113 @@
+import unittest
+from tap_marketo.client import Client, MAX_DAILY_CALLS
+
+class TestmaxdailycallsConfig(unittest.TestCase):
+    
+    def test_maxdailycalls_default_no_val(self):
+        """
+            Verify that max_daily_calls is default if no value is passed
+        """
+        # Initialize Client object
+        client = Client(**{'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT'})
+        
+        self.assertEqual(client.max_daily_calls, MAX_DAILY_CALLS)
+    
+    def test_maxdailycalls_default_empty_str(self):
+        """
+            Verify that max_daily_calls is default if empty string value is passed
+            Verify no Exception is raised for typecasting error between str to num
+        """
+        # Initialize Client object
+        client = Client(**{'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':''})
+        
+        self.assertEqual(client.max_daily_calls, MAX_DAILY_CALLS)
+
+    def test_maxdailycalls_default_bool_false_val(self):
+        """
+            Verify that max_daily_calls is default if bool value is passed
+        """
+        # Initialize Client object
+        client = Client(**{'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':False})
+        self.assertEqual(client.max_daily_calls ,MAX_DAILY_CALLS)
+
+    def test_maxdailycalls_bool_true_val(self):
+        """
+            Verify that max_daily_calls is default if bool value is passed
+        """
+        # Initialize Client object
+        params = {'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':True}
+        with self.assertRaises(ValueError):
+            try:
+                Client(**params)
+            except Exception as err:
+                self.assertEqual(str(err),"Limit Cannot be Negative or Zero")
+                raise err
+
+    def test_maxdailycalls_default_zero_val(self):
+        """
+            Verify that api_limit is default if 0 value is passed
+        """
+        # Initialize Client object
+        client = Client(**{'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':0})
+        self.assertEqual(client.max_daily_calls, MAX_DAILY_CALLS)
+
+    def test_maxdailycalls_default_none_val(self):
+        """
+            Verify that api_limit is default if None value is passed
+        """
+        # Initialize Client object
+        client = Client(**{'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':None})
+        self.assertEqual(client.max_daily_calls, MAX_DAILY_CALLS)
+
+    def test_maxdailycalls_enabled_num_val(self):
+        """
+            Verify that api_limit is set appropriately if num value is passed
+        """
+        # Initialize Client object
+        client = Client(**{'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':3})
+
+        self.assertEqual(client.max_daily_calls, 3)
+
+    def test_maxdailycalls_failed_comma_val(self):
+        """
+            Verify that exception is raised if invalid input value is passed
+        """
+        params = {'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':'30,000'}
+        # Initialize Client object
+        with self.assertRaises(ValueError):
+            Client(**params)
+
+    def test_maxdailycalls_failed_decimal_val(self):
+        """
+            Verify that api_limit is set appropriately if num value is passed
+        """
+        # Initialize Client object
+        params = {'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':'3700.15'}
+        with self.assertRaises(ValueError):
+            Client(**params)
+
+    def test_maxdailycalls_failed_negative_val(self):
+        """
+            Verify that api_limit is set appropriately if num value is passed
+        """
+        # Initialize Client object
+        params = {'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':'-522'}
+        with self.assertRaises(ValueError):
+            try:
+                Client(**params)
+            except Exception as err:
+                self.assertEqual(str(err),"Limit Cannot be Negative or Zero")
+                raise err
+
+    def test_maxdailycalls_default_str_zero_val(self):
+        """
+            Verify that api_limit is default if "0" value is passed
+        """
+        # Initialize Client object
+        params = {'endpoint': '123-ABC-789','client_id':'ABC-123','client_secret':'123-QRT','max_daily_calls':'0'}
+        with self.assertRaises(ValueError):
+            try:
+                Client(**params)
+            except Exception as err:
+                self.assertEqual(str(err),"Limit Cannot be Negative or Zero")
+                raise err