Sometimes the library gets stuck waiting for a session to be obtained, and this goes on for however long until the process is stopped. On restart, everything works normally again.
This is a long-running script so I'm not sure how to reproduce, but the gist of it is that it iterates through a number of mailboxes and handles emails in those mailboxes. The error seems to happen when one mailbox is trying to refresh its session, and a Timeout occurs. The next time the session is requested, it goes into this endless loop of waiting for a session and never receiving it.
[2025-09-07 23:17:32,645] [exchangelib.queryset] [DEBUG] Initializing cache
[2025-09-07 23:17:32,646] [exchangelib.folders.collections] [DEBUG] Finding email@email.com items in folders (Messages(Root(<exchangelib.account.Account object at 0x7b0b7dabe250>, '[self]', 'root', 24, 0, 98, None, 'xxxxxxxx', 'xxxxxxx'), None, None, None, None, None, 'xxxxxxx', None),) (shape: IdOnly, depth: Shallow, additional_fields: None, restriction: datetime_received > EWSDateTime(2025, 9, 7, 22, 9, 20, tzinfo=EWSTimeZone(key='UTC')))
[2025-09-07 23:17:32,647] [exchangelib.services.common] [DEBUG] Getting page at offset 0 (max_items 50)
[2025-09-07 23:17:32,648] [exchangelib.services.common] [DEBUG] Calling service FindItem
[2025-09-07 23:17:32,648] [exchangelib.services.common] [DEBUG] Trying API version Exchange2016
[2025-09-07 23:17:32,648] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Got session immediately
[2025-09-07 23:17:32,648] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Got session 75496
[2025-09-07 23:17:32,725] [urllib3.connectionpool] [DEBUG] https://outlook.office365.com:443 "POST /EWS/Exchange.asmx HTTP/11" 200 None
[2025-09-07 23:17:32,726] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Releasing session 75496
[2025-09-07 23:17:32,726] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: session 75496 usage exceeded limit. Discarding
[2025-09-07 23:17:32,726] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Renewing session 75496
[2025-09-07 23:17:32,733] [urllib3.connectionpool] [DEBUG] Starting new HTTPS connection (1): login.microsoftonline.com:443
requests.exceptions.ReadTimeout: HTTPSConnectionPool(host='login.microsoftonline.com', port=443): Read timed out. (read timeout=120)
raise ReadTimeout(e, request=request)
File "/opt/app/.venv/lib/python3.11/site-packages/requests/adapters.py", line 713, in send
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
r = adapter.send(request, **kwargs)
File "/opt/app/.venv/lib/python3.11/site-packages/requests/sessions.py", line 703, in send
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
resp = self.send(prep, **send_kwargs)
File "/opt/app/.venv/lib/python3.11/site-packages/requests/sessions.py", line 589, in request
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
return super(OAuth2Session, self).request(
File "/opt/app/.venv/lib/python3.11/site-packages/requests_oauthlib/oauth2_session.py", line 566, in request
^^^^^^^^^^^^^
r = self.request(
File "/opt/app/.venv/lib/python3.11/site-packages/requests_oauthlib/oauth2_session.py", line 381, in fetch_token
^^^^^^^^^^^^^^^^^^^^
token = session.fetch_token(
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/protocol.py", line 342, in create_oauth2_session
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
session = self.create_oauth2_session()
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/protocol.py", line 312, in create_session
^^^^^^^^^^^^^^^^^^^^^
return self.create_session()
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/protocol.py", line 287, in renew_session
^^^^^^^^^^^^^^^^^^^^^^^^^^^
session = self.renew_session(session)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/protocol.py", line 264, in release_session
self.protocol.release_session(session)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 365, in _get_response
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
r = self._get_response(payload=payload, api_version=api_version)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 396, in _get_response_xml
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
response = self._get_response_xml(payload=payload)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 784, in _response_generator
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
yield from self._response_generator(payload=payload)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 300, in _get_elements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
page_elems = list(self._get_elements(payload=payload))
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 898, in _get_pages
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pages = self._get_pages(payload_func, kwargs, len(paging_infos))
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 801, in _paged_call
for elem in elems:
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/services/common.py", line 216, in _elems_to_objs
yield from FindItem(account=self.account, page_size=page_size).call(
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/folders/collections.py", line 211, in find_items
^^^^^^^^^^^^^^
first = next(iterable)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/util.py", line 152, in peek
^^^^^^^^^^^
is_empty, items = peek(items)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/account.py", line 409, in _consume_item_service
yield from self._consume_item_service(
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/account.py", line 720, in fetch
for i in iterable:
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/queryset.py", line 345, in _item_yielder
yield from self._format_items(items=self._query(), return_format=self.return_format)
File "/opt/app/.venv/lib/python3.11/site-packages/exchangelib/queryset.py", line 270, in __iter__
File "pphe_email_processor/core/email_handler.py", line 119, in process_emails
During handling of the above exception, another exception occurred:
urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='login.microsoftonline.com', port=443): Read timed out. (read timeout=120)
raise ReadTimeoutError(
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 369, in _raise_timeout
self._raise_timeout(err=e, url=url, timeout_value=conn.timeout)
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 468, in _make_request
raise new_e
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 490, in _make_request
^^^^^^^^^^^^^^^^^^^
response = self._make_request(
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 789, in urlopen
raise value
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/util/util.py", line 39, in reraise
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
raise reraise(type(error), error, _stacktrace)
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/util/retry.py", line 474, in increment
^^^^^^^^^^^^^^^^^^
retries = retries.increment(
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 843, in urlopen
^^^^^^^^^^^^^
resp = conn.urlopen(
File "/opt/app/.venv/lib/python3.11/site-packages/requests/adapters.py", line 667, in send
The above exception was the direct cause of the following exception:
TimeoutError: _ssl.c:999: The handshake operation timed out
self._sslobj.do_handshake()
File "/usr/local/lib/python3.11/ssl.py", line 1382, in do_handshake
self.do_handshake()
File "/usr/local/lib/python3.11/ssl.py", line 1104, in _create
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
return self.sslsocket_class._create(
File "/usr/local/lib/python3.11/ssl.py", line 517, in wrap_socket
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
return ssl_context.wrap_socket(sock, server_hostname=server_hostname)
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/util/ssl_.py", line 509, in _ssl_wrap_socket_impl
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ssl_sock = _ssl_wrap_socket_impl(sock, context, tls_in_tls, server_hostname)
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/util/ssl_.py", line 465, in ssl_wrap_socket
^^^^^^^^^^^^^^^^
ssl_sock = ssl_wrap_socket(
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connection.py", line 805, in _ssl_wrap_socket_and_match_hostname
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sock_and_verified = _ssl_wrap_socket_and_match_hostname(
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connection.py", line 652, in connect
conn.connect()
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 1095, in _validate_conn
self._validate_conn(conn)
File "/opt/app/.venv/lib/python3.11/site-packages/urllib3/connectionpool.py", line 466, in _make_request
Traceback (most recent call last):
... # other calls for other mailboxes succeeding
[2025-09-07 23:20:41,307] [exchangelib.queryset] [DEBUG] Initializing cache
[2025-09-07 23:20:41,308] [exchangelib.folders.collections] [DEBUG] Finding email@email.com items in folders (Messages(Root(<exchangelib.account.Account object at 0x7b0b7dabe250>, '[self]', 'root', 24, 0, 98, None, 'xxxxxxxxxxxxxxxxxxxxxxx', 'xxxxxxxxxxxxxxxxxx'), None, None, None, None, None, 'xxxxxxxxxxxxxxxxx', None),) (shape: IdOnly, depth: Shallow, additional_fields: None, restriction: datetime_received > EWSDateTime(2025, 9, 7, 22, 9, 20, tzinfo=EWSTimeZone(key='UTC')))
[2025-09-07 23:20:41,308] [exchangelib.services.common] [DEBUG] Getting page at offset 0 (max_items 50)
[2025-09-07 23:20:41,309] [exchangelib.services.common] [DEBUG] Calling service FindItem
[2025-09-07 23:20:41,309] [exchangelib.services.common] [DEBUG] Trying API version Exchange2016
[2025-09-07 23:20:41,309] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:21:41,309] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:21:41,310] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:22:41,311] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:22:41,310] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:23:41,311] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:23:41,311] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:24:41,312] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:24:41,312] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:25:41,313] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:25:41,313] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:26:41,314] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:26:41,313] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:27:41,314] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:27:41,314] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:28:41,315] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
[2025-09-07 23:28:41,315] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: Waiting for session
[2025-09-07 23:29:41,316] [exchangelib.protocol] [DEBUG] Server outlook.office365.com: No sessions available for 60 seconds
As I had seen a big usage of memory and this was suggested as a way to limit it in a different issue here.
Sometimes the library gets stuck waiting for a session to be obtained, and this goes on for however long until the process is stopped. On restart, everything works normally again.
This is a long-running script so I'm not sure how to reproduce, but the gist of it is that it iterates through a number of mailboxes and handles emails in those mailboxes. The error seems to happen when one mailbox is trying to refresh its session, and a Timeout occurs. The next time the session is requested, it goes into this endless loop of waiting for a session and never receiving it.
Maybe relevant information is that I have added this to the script:
As I had seen a big usage of memory and this was suggested as a way to limit it in a different issue here.
exchangelib: 5.4.2, python: 3.11