diff --git a/lib/sendgrid_toolkit/abstract_sendgrid_client.rb b/lib/sendgrid_toolkit/abstract_sendgrid_client.rb
index 5bd6ed7..d0625d9 100644
--- a/lib/sendgrid_toolkit/abstract_sendgrid_client.rb
+++ b/lib/sendgrid_toolkit/abstract_sendgrid_client.rb
@@ -16,12 +16,12 @@ def api_post(module_name, action_name, opts = {})
       response = HTTParty.post("https://#{SendgridToolkit.base_uri}/#{base_path}.json",
                                :body => get_credentials.merge(opts),
                                :format => :json)
-      if response.code > 401
+      if response.code > 403
         raise(SendgridToolkit::SendgridServerError, "The SendGrid server returned an error. #{response.inspect}")
-      elsif has_error?(response) and
-          response['error'].respond_to?(:has_key?) and
-          response['error'].has_key?('code') and
-          response['error']['code'].to_i == 401
+      elsif has_error?(response) &&
+          response['error'].respond_to?(:has_key?) &&
+          response['error'].has_key?('code') &&
+          [401, 403].include?(response['error']['code'].to_i)
         raise SendgridToolkit::AuthenticationFailed
       elsif has_error?(response)
         raise(SendgridToolkit::APIError, response['error'])
diff --git a/spec/lib/sendgrid_toolkit/abstract_sendgrid_client_spec.rb b/spec/lib/sendgrid_toolkit/abstract_sendgrid_client_spec.rb
index 6188eaf..2d201d1 100644
--- a/spec/lib/sendgrid_toolkit/abstract_sendgrid_client_spec.rb
+++ b/spec/lib/sendgrid_toolkit/abstract_sendgrid_client_spec.rb
@@ -16,6 +16,13 @@
         @obj.send(:api_post, "profile", "get", {})
       }.should raise_error SendgridToolkit::AuthenticationFailed
     end
+    it "throws error when bad username or password presented" do
+      FakeWeb.register_uri(:post, %r|https://#{REGEX_ESCAPED_BASE_URI}/stats\.getAdvanced\.json\?|, :body => '{"error":{"code":403,"message":"Bad username / password"}}', :status => ['403', 'Forbidden'])
+      @obj = SendgridToolkit::AbstractSendgridClient.new("fakeuser", "fakepass")
+      expect {
+        @obj.send(:api_post, "stats", "getAdvanced", {})
+      }.to raise_error SendgridToolkit::AuthenticationFailed
+    end
     it "thows error when sendgrid response is a server error" do
       FakeWeb.register_uri(:post, %r|https://#{REGEX_ESCAPED_BASE_URI}/profile\.get\.json|, :body => '{}', :status => ['500', 'Internal Server Error'])
       @obj = SendgridToolkit::AbstractSendgridClient.new("someuser", "somepass")