When running Web Agent and protecting an application with the "Multi-Factor Authentication Chain Template", once the user tries to log in with the HTML Form (Primary Authentication Scheme), the browser gets redirected back to the HTML Form.
As per documentation, the "Multi-Factor Authentication Chain Template" is part of the integration with VIP Authentication Hub, and this feature is only available on CA Access Gateway (SPS) from version 12.8SP6 (1).
"Multi-Factor Authentication Chain Template" won't work on Web Agent 12.52SP1CR11 on IIS 10 on Windows 2016.
This is why the browser doesn’t go to the VIP Authentication Hub.
Fully implement the "Multi-Factor Authentication Chain Template" on CA Access Gateway (SPS) 12.8SP7 to solve this issue.