Windows Server · Python hosting
NameError: dash is not defined (Did you mean Dash?)
You imported from dash import Dash but called dash.Dash(...). One-line import fix before you chase IIS.
What you’re seeing
Deploy or import fails with NameError: name 'dash' is not defined. Did you mean: 'Dash'?
Why it happens
You wrote from dash import Dash but called dash.Dash(...). The name dash was never bound — only Dash was.
The fix
from dash import Dash app = Dash(__name__) # not dash.Dash(__name__) server = app.server
Or keep dash.Dash(...) and add import dash.
Avoid this class of problem
When you publish through iVistaar, preflight and runtime logs surface this import error immediately on the deployment page instead of a silent IIS 500.
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.