RemoteProtocolError problem

[licx0322]

My code is:
self.client = httpx.Client(http2=True, verify=False) r = self.client.post(url, headers=headers, data=data, files=None, timeout=20)
The code above works well most of the time, but the exception bellow sometimes occurs:

Traceback (most recent call last): File "/root/TDC-autocase/core/http2.py", line 76, in post r = self.client.post(url, headers=headers, data=data, files=files, timeout=timeout) File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_client.py", line 1115, in post timeout=timeout, File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_client.py", line 786, in request request, auth=auth, allow_redirects=allow_redirects, timeout=timeout File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_client.py", line 876, in send history=[], File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_client.py", line 911, in _send_handling_auth history=history, File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_client.py", line 943, in _send_handling_redirects response = self._send_single_request(request, timeout) File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_client.py", line 982, in _send_single_request extensions={"timeout": timeout.as_dict()}, File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_transports/default.py", line 186, in handle_request extensions=extensions, File "/usr/local/python3.7/lib/python3.7/contextlib.py", line 130, in __exit__ self.gen.throw(type, value, traceback) File "/usr/local/python3.7/lib/python3.7/site-packages/httpx/_transports/default.py", line 78, in map_httpcore_exceptions raise mapped_exc(message) from exc httpx.RemoteProtocolError:

Nothing wrong with the server, the server replies response normally.
I don't know whats wrong. Please help.

[licx0322]

Why the error detail is None?
httpx.RemoteProtocolError: