Windows Server · Python hosting
cannot import name 'app' (Dash / Flask entrypoint)
Deploy fails because the entrypoint points at a Dash object, not the Flask WSGI server. Use app:server / run:server.
What you’re seeing
Deploy fails with an import error such as cannot import name 'app', Waitress cannot load the target, or Connect reports Could not resolve entrypoint listing files like run.py and capture_snapshot.py.
Why it happens
Flask apps usually expose app (WSGI). Dash apps expose a Dash instance — Waitress needs the Flask server object. Using app:app on a Dash project looks for the wrong attribute when there is no app.py. Helper scripts in the project root (for example capture_snapshot.py next to run.py) used to block auto-detect. Some tools also try to pip install app from PyPI when the local module is missing — that installs junk.
The fix
- Flask: entrypoint
app:app - Dash:
server = app.serverand entrypointapp:serverorrun:servermatching the filename - Confirm the module file exists in the connected folder before deploy
Avoid this class of problem
iVistaar detects common stacks and refuses to blindly pip install app from PyPI when your local entrypoint is wrong — you get a clear entrypoint error instead.
Publish without the IIS tax
iVistaar is an internal deployment control plane for Windows Server/IIS that gives Flask, Dash, and Streamlit apps an org URL without Git or cloud services. Free demo includes 3 sites.