Why I’m getting this authentication message as I start the Geocortex?

Why I’m getting this authentication message as I start the Geocortex?

I couldn’t figure Why I’m getting the authentication message below:

/customer/servlet/servlet.FileDownload?file=00P6000000eltzMEAQ

At which level this authentication is set? Is it windows authentication? Geocortex authentication?

Thank you

Best

Jamal