In my previous question, I asked how to make mod_wsgi use a specific Python version. Following the answer from that question, I created a Python 3.9 virtual environment and made WSGI use it. However, now my Flask app is not running at all - I just get the 404 page configured for the rest of my site. I get no errors when restarting Apache2 and the Apache error log is empty when I visit the site. I think the error must be due to my virtual environment, as I have created previous test Flask apps before using the same config style.
My virtual environment is located in
# Make something appear in error log if the WSGI is run at all
PROJECT_DIR = os.path.dirname(os.path.realpath(__file__))
from my_app import app as application
WSGIDaemonProcess myapp user=www-data group=www-data threads=4 python-home=/path/to/my/app/venv/
WSGIScriptAlias /my-app/ path/to/my/app/runner.wsgi
LoadModule wsgi_module "/path/to/my/app/venv/lib/python3.9/site-packages/mod_wsgi/server/mod_wsgi-py39.cpython-39-x86_64-linux-gnu.so"
OS: Ubuntu 18.04.5 LTS