diff --git a/cdsodatacli/download.py b/cdsodatacli/download.py
index 0b976e6..5500c3e 100644
--- a/cdsodatacli/download.py
+++ b/cdsodatacli/download.py
@@ -8,6 +8,7 @@
 import shutil
 import random
 import pandas as pd
+from requests.exceptions import ChunkedEncodingError
 from concurrent.futures import ThreadPoolExecutor, as_completed
 import numpy as np
 import traceback
@@ -26,7 +27,8 @@
 from cdsodatacli.utils import conf, test_safe_archive, test_safe_spool
 from collections import defaultdict
 
-chunksize = 4096
+# chunksize = 4096
+chunksize = 8192  # like in the CDSE example
 
 # def CDS_Odata_download_one_product(session, headers, url, output_filepath):
 #     """
@@ -94,23 +96,36 @@ def CDS_Odata_download_one_product_v2(
     # output_filepath_tmp = (
     #     output_filepath.replace(conf["spool"], conf["pre_spool"]) + ".tmp"
     # )
-    output_filepath_tmp = os.path.join(conf["pre_spool"],os.path.basename(output_filepath)+ ".tmp")
+    output_filepath_tmp = os.path.join(
+        conf["pre_spool"], os.path.basename(output_filepath) + ".tmp"
+    )
     safename_base = os.path.basename(output_filepath).replace(".zip", "")
     with open(output_filepath_tmp, "wb") as f:
         logging.debug("Downloading %s" % output_filepath)
         response = session.get(url, headers=headers, stream=True)
         status = response.status_code
         status_meaning = response.reason
+        # Check for 'Transfer-Encoding: chunked'
+        if (
+            "Transfer-Encoding" in response.headers
+            and response.headers["Transfer-Encoding"] == "chunked"
+        ):
+            logging.warning(
+                "Server is using 'Transfer-Encoding: chunked'. Content length may not be accurate."
+            )
         if response.ok:
             total_length = int(
                 int(response.headers.get("content-length")) / 1000 / 1000
             )
             logging.debug("total_length : %s Mo", total_length)
-
-            for chunk in response.iter_content(chunk_size=8192):
-                if chunk:
-                    f.write(chunk)
-    if not response.ok and os.path.exists(output_filepath_tmp):
+            try:
+                for chunk in response.iter_content(chunk_size=chunksize):
+                    if chunk:
+                        f.write(chunk)
+            except ChunkedEncodingError as e:
+                status = -1
+                status_meaning = "ChunkedEncodingError"
+    if (not response.ok or status == -1) and os.path.exists(output_filepath_tmp):
         logging.debug("remove empty file %s", output_filepath_tmp)
         os.remove(output_filepath_tmp)
     elapsed_time = time.time() - t0
@@ -250,7 +265,7 @@ def download_list_product_multithread_v2(
                     login=login,
                     date_generation_access_token=date_generation_access_token,
                 )
-                logging.info('remove session semaphore for %s',login)
+                logging.info("remove session semaphore for %s", login)
                 remove_semaphore_session_file(
                     session_dir=conf["active_session_directory"],
                     safename=safename_base,
@@ -272,7 +287,7 @@ def download_list_product_multithread_v2(
                 else:
                     df2.loc[(df2["safe"] == safename_base), "status"] = -1
                     errors_per_account[login] += 1
-                    logging.info('error found for %s meaning %s',login,status_meaning)
+                    logging.info("error found for %s meaning %s", login, status_meaning)
                     # df2["status"][df2["safe"] == safename_base] = -1 # download in error
                 cpt["status_%s" % status_meaning] += 1
 
@@ -374,7 +389,7 @@ def download_list_product(
                         access_token,
                         date_generation_access_token,
                         specific_account,
-                        path_semphore_token
+                        path_semphore_token,
                     ) = get_bearer_access_token(specific_account=specific_account)
                     headers = {"Authorization": "Bearer %s" % access_token}
                     session.headers.update(headers)
@@ -454,7 +469,7 @@ def download_list_product_sequential(
 
     """
     assert len(list_id) == len(list_safename)
-    logins_group = 'logins'
+    logins_group = "logins"
     cpt = defaultdict(int)
     cpt["total_product_to_download"] = len(list_id)
     df = pd.DataFrame(
@@ -463,7 +478,10 @@ def download_list_product_sequential(
     df2, cpt = filter_product_already_present(cpt, df, outputdir)
 
     df_products_downloadable = get_sessions_download_available(
-        df2, hideProgressBar=hideProgressBar, blacklist=None,logins_group=logins_group,
+        df2,
+        hideProgressBar=hideProgressBar,
+        blacklist=None,
+        logins_group=logins_group,
     )
     logging.info("product downloadable: %s", len(df_products_downloadable))
     df_products_downloadable["status"] = 0
@@ -506,8 +524,10 @@ def download_list_product_sequential(
                 access_token,
                 date_generation_access_token,
                 login,
-                path_semaphore_token
-            ) = get_bearer_access_token(specific_account=None,account_group=logins_group)
+                path_semaphore_token,
+            ) = get_bearer_access_token(
+                specific_account=None, account_group=logins_group
+            )
             headers = {"Authorization": "Bearer %s" % access_token}
             session.headers.update(headers)
         else:
diff --git a/cdsodatacli/fetch_access_token.py b/cdsodatacli/fetch_access_token.py
index b396fd3..11e214f 100644
--- a/cdsodatacli/fetch_access_token.py
+++ b/cdsodatacli/fetch_access_token.py
@@ -33,12 +33,13 @@ def get_bearer_access_token(quiet=True, specific_account=None, account_group="lo
         prefix = "curl -s "
     else:
         prefix = "curl "
+    option_insecure = ' --insecure' # added because workers have deprecated SSL certificates
     cmd = (
         prefix
         + " --location --request POST "
         + url_identity
-        + " --header 'Content-Type: application/x-www-form-urlencoded' --data-urlencode 'grant_type=password' --data-urlencode 'username=%s' --data-urlencode 'password=%s' --data-urlencode 'client_id=cdse-public'"
-        % (login, passwd)
+        + " --header 'Content-Type: application/x-www-form-urlencoded' --data-urlencode 'grant_type=password' --data-urlencode 'username=%s' --data-urlencode 'password=%s' --data-urlencode 'client_id=cdse-public' %s"
+        % (login, passwd,option_insecure)
     )
 
     logging.debug("cmd: %s", cmd)