diff --git a/lib/twilio-ruby/base/client_base.rb b/lib/twilio-ruby/base/client_base.rb
index b0904c135..a52b0e812 100644
--- a/lib/twilio-ruby/base/client_base.rb
+++ b/lib/twilio-ruby/base/client_base.rb
@@ -52,7 +52,7 @@ def request(host, port, method, uri, params = {}, data = {}, headers = {}, auth
           @logger.debug("Request Params:#{params}")
         end
 
-        auth = @credential_provider.to_auth_strategy.auth_string if @credential_provider
+        auth = @credentials.to_auth_strategy.auth_string unless @credentials.nil?
 
         response = @http_client.request(
           host,