ModuleNotFoundError: No module named 'requests'

Python cannot find the 'requests' package in the active interpreter. 1. Install it: `pip install requests` (or `python -m pip install requests` to be sure you hit the right interpreter). 2. Verify which Python is running your script: `which python` / `python -c "import sys; print(sys.executable)"`. If it differs from the one you used for pip, install into that one: `/path/to/python -m pip install requests`. 3. Virtualenv: activate it first (`source .venv/bin/activate`), then `pip install requests`. 4. If using requirements.txt, make sure `requests` is listed and run `pip install -r requirements.txt`. 5. For scripts run by cron/systemd, set the full path to the venv Python in the unit/cron entry.