When going through the NetScaler, the following error is seen in the Event Viewer: An authentication request was made before establishing a web session. This typically occurs when sticky load-balancing between client and StoreFront is misconfigured.

1. On the Storefront server enable 'User name and password' as an authentication method
2. Add "C:\Windows\System32\inetsrv\w3wp.exe" to Anti-Virus exclusion scan list​. 
3. Turn off Application Firewall on NetScaler

Problem Cause

• User name and password were not enabled as an Authentication Method on the StoreFront Server
• Application Firewall was turned on, on the NetScaler.