diff --git a/twilio/http/client_token_manager.py b/twilio/http/client_token_manager.py
index 0d42428a2f..d65acb2ba2 100644
--- a/twilio/http/client_token_manager.py
+++ b/twilio/http/client_token_manager.py
@@ -29,7 +29,7 @@ def __init__(
         self.client = Client()
 
     def fetch_access_token(self):
-        token_instance = self.client.iam.v1.token.create(
+        token_instance = self.client.preview_iam.v1.token.create(
             grant_type=self.grant_type,
             client_id=self.client_id,
             client_secret=self.client_secret,
diff --git a/twilio/http/orgs_token_manager.py b/twilio/http/orgs_token_manager.py
index 76fad5213f..767ed270af 100644
--- a/twilio/http/orgs_token_manager.py
+++ b/twilio/http/orgs_token_manager.py
@@ -29,7 +29,7 @@ def __init__(
         self.client = Client()
 
     def fetch_access_token(self):
-        token_instance = self.client.iam.v1.token.create(
+        token_instance = self.client.preview_iam.v1.token.create(
             grant_type=self.grant_type,
             client_id=self.client_id,
             client_secret=self.client_secret,