diff --git a/watcherclient/common/httpclient.py b/watcherclient/common/httpclient.py
index 674a992..f9ee71b 100644
--- a/watcherclient/common/httpclient.py
+++ b/watcherclient/common/httpclient.py
@@ -20,6 +20,7 @@ import http.client
 import io
 import logging
 import os
+import re
 import socket
 import ssl
 import textwrap
@@ -61,7 +62,7 @@ SUPPORTED_ENDPOINT_SCHEME = ('http', 'https')
 
 def _trim_endpoint_api_version(url):
     """Trim API version and trailing slash from endpoint."""
-    return url.rstrip('/').rstrip(API_VERSION)
+    return re.sub(f'{API_VERSION}$', '', url.rstrip('/'))
 
 
 def _extract_error_json(body):
diff --git a/watcherclient/tests/unit/test_client.py b/watcherclient/tests/unit/test_client.py
index 4d12419..fd229b6 100644
--- a/watcherclient/tests/unit/test_client.py
+++ b/watcherclient/tests/unit/test_client.py
@@ -358,3 +358,8 @@ class ClientTest(utils.BaseTestCase):
         client = httpclient.HTTPClient(endpoint)
         conn_url = client._make_connection_url(url)
         self.assertEqual(expected_url, conn_url)
+
+    def test_port_ends_with_one(self):
+        endpoint = "http://localhost:8081/"
+        http_client = httpclient.HTTPClient(endpoint)
+        self.assertEqual(endpoint, http_client._make_connection_url(""))