Hi,

 

Please test this appSettings in web.config :

 

 <add key="CuteWebUI.AjaxUploader.AllowSession" value="True" />
 <add key="CuteWebUI.AjaxUploader.UseAspNetStream" value="True"/>

 

(Please test True/True , True/False , False/True )

 

It may helps for determining the reason.

 

Regards,

Terry