Solved: session max execution timeout HttpRuntimeSection.MaxRequestLength without session timeout

<sessionState mode="InProc" timeout="540" />
    <httpRuntime maxRequestLength="2147483647" shutdownTimeout="360" executionTimeout="3600"/>

Also debug should be false in <compilation debug="false" targetFramework="4.0">

The MaxRequestLength property specifies the limit for the buffering threshold of the input stream. For example, this limit can be used to prevent denial of service attacks that are caused by users who post large files to the server.

The value assigned to this property should be greater or equal to value assigned to the RequestLengthDiskThreshold property.