We have developed a MVCToPDF application that runs fine on IISExpress.  The application runs with Windows Authentication.  We we deploy the application to a server, we get 401.2 errors when the page loads the CSS and JS files.  I found a forum post that is similar to this problem that explains how the EO browser gets its user settings.  
https://www.essentialobjects.com/forum/postst7179_ASPXToPDF-trial-output-different-on-test-system-than-dev-system.aspx This post suggests that we turn on impersonation or turn off permission on the CSS files.  We have attempted both of these settings and it has not made a difference.  
We are running the 19.0.83.0 release of OE.  Any help would be appreciated.