Check the Working Set Limits in the QlikView Management Console (QMC). If the server has reached the "Low" or "High" memory limit, it will drop sessions or fail to open new ones.
Clear your cache and try an Incognito/Private window. the document failed to load qlikview
Restart the QlikView Server and QlikView Web Servers services in the Windows Services panel. Check the Working Set Limits in the QlikView
The on your server versus the size of the .qvw file . the document failed to load qlikview