diff --git a/okx/__init__.py b/okx/__init__.py
index 1d14033..9c8f727 100644
--- a/okx/__init__.py
+++ b/okx/__init__.py
@@ -2,4 +2,4 @@
 Python SDK for the OKX API v5
 
 """
-__version__="0.1.7"
\ No newline at end of file
+__version__="0.1.8"
\ No newline at end of file
diff --git a/okx/client.py b/okx/client.py
index 0f5e652..25c8a3d 100644
--- a/okx/client.py
+++ b/okx/client.py
@@ -1,18 +1,13 @@
 import json
-import time
-import traceback
 
 import httpx
-from httpx import _client
 
-from . import consts as c, utils
+from . import consts as c, utils, exceptions
 
 
 class Client(object):
 
-    def __init__(self, api_key='-1', api_secret_key='-1', passphrase='-1', use_server_time=False, flag='1',
-                 base_api=c.DOMAIN, debug=False):
-
+    def __init__(self, api_key = '-1', api_secret_key = '-1', passphrase = '-1', use_server_time=False, flag='1', base_api = c.API_URL,debug = 'True'):
         self.API_KEY = api_key
         self.API_SECRET_KEY = api_secret_key
         self.PASSPHRASE = passphrase
@@ -20,8 +15,7 @@ class Client(object):
         self.flag = flag
         self.domain = base_api
         self.debug = debug
-        self.request_times = 0
-        self.client = httpx.Client(base_url=base_api, http2=True, verify=False, timeout=None)
+        self.client = httpx.Client(base_url=base_api, http2=True)
 
     def _request(self, method, request_path, params):
         if method == c.GET:
@@ -31,57 +25,32 @@ class Client(object):
             timestamp = self._get_timestamp()
         body = json.dumps(params) if method == c.POST else ""
         if self.API_KEY != '-1':
-            sign = utils.sign(utils.pre_hash(timestamp, method, request_path, str(body), self.debug),
-                              self.API_SECRET_KEY)
+            sign = utils.sign(utils.pre_hash(timestamp, method, request_path, str(body), self.debug), self.API_SECRET_KEY)
             header = utils.get_header(self.API_KEY, sign, timestamp, self.PASSPHRASE, self.flag, self.debug)
         else:
             header = utils.get_header_no_sign(self.flag, self.debug)
         response = None
-        if self.debug:
-            print('domain:', self.domain)
-            print('url:', request_path)
+        if self.debug == True:
+            print('domain:',self.domain)
+            print('url:',request_path)
         if method == c.GET:
             response = self.client.get(request_path, headers=header)
         elif method == c.POST:
             response = self.client.post(request_path, data=body, headers=header)
-        self.request_times += 1
-        if self.request_times > 512:
-            self.client.close()
-            self.client._state = _client.ClientState.UNOPENED
-            self.request_times = 0
-        return response
-
-    def _request_until_success(self, method, request_path, params):
-        response = ''
-        retry_times = 0
-        while True:
-            try:
-                response = self._request(method, request_path, params)
-                if not str(response.status_code).startswith('2'):
-                    print('response.status_code:', response.status_code)
-                    print('response.json.code:', response.json()['code'])
-                    print('response.json.msg:', response.json()['msg'])
-                    time.sleep(1)
-                    continue
-                break
-            except Exception as e:
-                traceback.format_exc()
-                print(e)
-                retry_times += 1
-                print('http request retry in 1 seconds, retry times:', retry_times)
-                time.sleep(1)
+        if not str(response.status_code).startswith('2'):
+            raise exceptions.OkxAPIException(response)
         return response.json()
 
     def _request_without_params(self, method, request_path):
-        return self._request_with_params(method, request_path, {})
+        return self._request(method, request_path, {})
 
     def _request_with_params(self, method, request_path, params):
-        return self._request_until_success(method, request_path, params)
+        return self._request(method, request_path, params)
 
     def _get_timestamp(self):
-        request_path = self.domain + c.SERVER_TIMESTAMP_URL
+        request_path = c.API_URL + c.SERVER_TIMESTAMP_URL
         response = self.client.get(request_path)
         if response.status_code == 200:
             return response.json()['ts']
         else:
-            return ""
+            return ""
\ No newline at end of file
diff --git a/okx/consts.py b/okx/consts.py
index ebb96c2..649e843 100644
--- a/okx/consts.py
+++ b/okx/consts.py
@@ -1,5 +1,5 @@
 # http header
-DOMAIN = 'https://www.okx.com'
+API_URL = 'https://www.okx.com'
 
 CONTENT_TYPE = 'Content-Type'
 OK_ACCESS_KEY = 'OK-ACCESS-KEY'