Broken pipe (socket) sending emails

[Naxest]

When I try to send big emails (around 12Mb), it fails with the next stack:

    httplib_response = self._make_request(
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 387, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/usr/lib/python3.8/http/client.py", line 1255, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1301, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1250, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1049, in _send_output
    self.send(chunk)
  File "/usr/lib/python3.8/http/client.py", line 971, in send
    self.sock.sendall(data)
  File "/usr/lib/python3.8/ssl.py", line 1204, in sendall
    v = self.send(byte_view[count:])
  File "/usr/lib/python3.8/ssl.py", line 1173, in send
    return self._sslobj.write(data)
BrokenPipeError: [Errno 32] Broken pipe

I was debugging and it happens when it try to upload the second attachment, with the endpoint:
https://graph.microsoft.com/beta/users/<user-id>/messages/<message-id>/attachments

I've try with MSGraphProtocol(api_version="beta") but it fails with the same error.

Maybe am I doing something wrong?

[Naxest]

I see this library doesn't have support for createUploadSession and upload attachments > 4Mb.

I'm going to make a PR.

[alejcas]

Nope, it’s planned but not done yet. See #476