This error happens because of how Python resolves imports. If your project looks like:

repo/
├── src/
│   ├── __init__.py
│   └── test.py

then:

• From the project root (repo/):

  uvicorn src.test:app --reload
  
  

• From inside src/:

  uvicorn test:app --reload
  
  

uvicorn src.test:app only works when you run it from the directory that contains src.

Do you want to share what your folder structure looks like to better look into this?