SYMPTOM:
User is redirected to the standard login page when login to a project with Windows Authentication is enabled in Web Administrator in Strategy Web 9.x and 10.x

CAUSE:
Windows Authentication is enabled by default in Strategy Web Administrator > Default Properties > Login, but is not enabled by default under Web Preferences > Project Default > Login modes, as shown below:

ACTION:
Enable Windows Authentication as default login mode under Web Preferences > Project Default > Login modes