python 3.12.7 Pydantic issue on mod_wsgi server module not found

[LaZyProjectsUK]

So I have a local version (windows) and a VPS server running ubunbu 22.04 and Apache2 with both running python 3.12.7 The local machine runs fine and works without issue. Running the same versions of pydantic and pydantic_core and openai on both I get errors on the server side:

openai==1.54.3 pydantic==2.9.2 pydantic_core==2.23.4

[Thu Nov 07 12:28:48.353345 2024] [wsgi:error] [pid 509021] [remote] from .batch import Batch as Batch
[Thu Nov 07 12:28:48.353351 2024] [wsgi:error] [pid 509021] [remote] File "/var/www/python.lazyprojects.co.uk/gpt/venv/lib/python3.12/site-packages/openai/types/batch.py", line 7, in
[Thu Nov 07 12:28:48.353355 2024] [wsgi:error] [pid 509021] [remote] from .._models import BaseModel
[Thu Nov 07 12:28:48.353360 2024] [wsgi:error] [pid 509021] [remote ] File "/var/www/python.lazyprojects.co.uk/gpt/venv/lib/python3.12/site-packages/openai/_models.py", line 24, in
[Thu Nov 07 12:28:48.353364 2024] [wsgi:error] [pid 509021] [remote ] from pydantic.fields import FieldInfo
[Thu Nov 07 12:28:48.353369 2024] [wsgi:error] [pid 509021] [remote] File "/var/www/python.lazyprojects.co.uk/gpt/venv/lib/python3.12/site-packages/pydantic/fields.py", line 17, in
[Thu Nov 07 12:28:48.353373 2024] [wsgi:error] [pid 509021] [remote] from pydantic_core import PydanticUndefined
[Thu Nov 07 12:28:48.353381 2024] [wsgi:error] [pid 509021] [remote ] File "/var/www/python.lazyprojects.co.uk/gpt/venv/lib/python3.12/site-packages/pydantic_core/init.py", line 6, in
[Thu Nov 07 12:28:48.353387 2024] [wsgi:error] [pid 509021] [remote ] from ._pydantic_core import (
[Thu Nov 07 12:28:48.353424 2024] [wsgi:error] [pid 509021] [remote ] ModuleNotFoundError: No module named 'pydantic_core._pydantic_core'

Having googled it, I see lots about Lambda but I am not using any of that. So I am not sure why this is happening. Can anyone help?

[LaZyProjectsUK]

Just out of interest, I created a new python project in both 3.11.9 and 3.12.7 on the vps server and installed openai, which requires Pydantic and Pydantic_core, and I get the same error as the above. These are clean install experiments, so the issue seems not to be existing dependencies.