diff --git a/envio_contrato_docs_email.py b/envio_contrato_docs_email.py
index 6265cff..4020cd3 100644
--- a/envio_contrato_docs_email.py
+++ b/envio_contrato_docs_email.py
@@ -1,7 +1,4 @@
 
-from google.auth.transport.requests import Request
-from google_auth_oauthlib.flow import InstalledAppFlow
-from google.oauth2.credentials import Credentials
 from google.oauth2 import service_account
 from googleapiclient.discovery import build
 import os
@@ -25,8 +22,8 @@ if os.path.isdir(libs_dir) and libs_dir not in sys.path:
 
 SCOPES = {scopes_api_google}
 
-CREDENTIALS_PATH = '{gdoc_sa_json}'
-TOKEN_PATH = '{gmail_token_json}'
+CREDENTIALS_PATH = '{gdoc_sa_json2}'
+IMPERSONATED_USER = '{gdoc_impersonated_user}'
 
 
 def _load_json(path):
@@ -34,39 +31,17 @@ def _load_json(path):
         return json.load(f)
 
 
-def get_drive_and_gmail_services(credentials_json_path=CREDENTIALS_PATH, token_json_path=TOKEN_PATH):
+def get_drive_and_gmail_services(credentials_json_path=CREDENTIALS_PATH, impersonated_user=IMPERSONATED_USER):
     info = _load_json(credentials_json_path)
+    if not isinstance(info, dict) or info.get('type') != 'service_account':
+        raise RuntimeError('gdoc_sa_json2 debe apuntar a un JSON de cuenta de servicio.')
 
-    # Service account
-    if isinstance(info, dict) and info.get('type') == 'service_account':
-        creds = service_account.Credentials.from_service_account_file(
-            credentials_json_path, scopes=SCOPES)
-        drive_service = build(
-            'drive', 'v3', credentials=creds, cache_discovery=False)
-        gmail_service = build(
-            'gmail', 'v1', credentials=creds, cache_discovery=False)
-        return drive_service, gmail_service
-
-    # OAuth flow
-    creds = None
-    if os.path.exists(token_json_path):
-        creds = Credentials.from_authorized_user_file(token_json_path, SCOPES)
-
-    if not creds or not creds.valid:
-        if creds and creds.expired and creds.refresh_token:
-            creds.refresh(Request())
-        else:
-            flow = InstalledAppFlow.from_client_secrets_file(
-                credentials_json_path, SCOPES)
-            try:
-                creds = flow.run_local_server(port=0)
-            except Exception:
-                creds = flow.run_console()
-
-        os.makedirs(os.path.dirname(token_json_path), exist_ok=True)
-        with open(token_json_path, 'w', encoding='utf-8') as f:
-            f.write(creds.to_json())
+    impersonated_user = (impersonated_user or '').strip()
+    if not impersonated_user:
+        raise RuntimeError('Falta la variable gdoc_impersonated_user.')
 
+    creds = service_account.Credentials.from_service_account_file(
+        credentials_json_path, scopes=SCOPES, subject=impersonated_user)
     drive_service = build(
         'drive', 'v3', credentials=creds, cache_discovery=False)
     gmail_service = build(
@@ -121,7 +96,7 @@ def send_email(gmail_service, to_emails, subject, body_text, attachment_bytes, a
 
 
 drive_service, gmail_service = get_drive_and_gmail_services(
-    CREDENTIALS_PATH, TOKEN_PATH)
+    CREDENTIALS_PATH, IMPERSONATED_USER)
 
 # Id del documento de Google Drive a enviar por email
 DOC_ID = '{gdoc_id}'