How to  Integrate onWeb  web-to-host session Configuration Manager into DotNet web Apllication?

Hello Vaibhav,
not sure what you need to accomplish if below information is not sufficient please elaborate a bit and describe your requirements.
The Web-to-Host product comes with two technologies.
a. ActiveX Controls
b. Java Applets

You can a reference the ActiveX Control (for example the Mainframe Display Control) in Visual Studio .NET

Start Visual Studio .NET and create either a new Visual Basic .NET Windows application or a Visual C# Windows application. The remaining steps apply to either language.
Select Tools, Customize Toolbox... from the menu, or right-click inside the Toolbox window and select Customize Toolbox... from the context menu. There are two kinds of controls that can be referenced: COM Components and .NET Framework Components. The default COM Components tab shows a list of all the registered ActiveX controls on the computer.

Please note:
With the the withdrawal of support for Internet Explorer 11 and ActiveX, together with the restriction of Java applets by modern browsers,we added a web launcher feature in Web-to-Host 6.9.2
The Host Access Web Launcher provides alternate means of running host sessions. As well as Internet Explorer 11, the Host Access Web Launcher provides the new ability of running the
same host sessions using Chrome, Edge, or Firefox. When you start a Web-to-Host session from a supported browser, the Web Launcher starts and opens the the Web-to-Host session itself.

That's correct for the Web-to-Host product version 6.9.2.
Web-to-Host detects the Browser , if you use Chrome, Edge, or Firefox it will  use the launcher to run the session.  With IE11 Web-to-Host will start in the browser context because IE11 still supports Java Applets and ActiveX controls.

Reflection ZFE  is a different product.
With ZFE we deliver a Java-free solution. It's a HTML5-based emulation with a true zero-footprint client.
You can find more details under here.

1. Can it support for AS/400 Mainframe system Connectivity ? and should I Integrate in Asp.net Web Forms or else into the Asp.Net Mvc ?

Hi Vaibhav,
we support ibm mainframe (3270) connectivity as well AS/400 (5250) connectivity.
You can use the provides components in your Application.
.net developers use the Rumba DeveloperEdition for VisualStudio.
RDE .NET is an Addin that appears in the Microsoft Visual Studio Toolbox as Mainframe, AS/400, UNIX and HP displays. RDE .NET components are objects that are available for you to use in .NET code to add mainframe and AS/400 printing, HLLAPI, macros and FTX functionality to your Visual Studio projects.

This is the wrong forum to address Reflection ZFE issues.
Please re-post your question into the Reflection ZFE forum.

Review your container.log file under  MSS\\server\\logs and check if the mss service is running correctly.
The Host Access Management and Security Server (MSS) provides the Administrative Console, a web-based centralized location where you can add, edit, and delete terminal sessions.

That's correct for the Web-to-Host product version 6.9.2.
Web-to-Host detects the Browser , if you use Chrome, Edge, or Firefox it will  use the launcher to run the session.  With IE11 Web-to-Host will start in the browser context because IE11 still supports Java Applets and ActiveX controls.

Reflection ZFE  is a different product.
With ZFE we deliver a Java-free solution. It's a HTML5-based emulation with a true zero-footprint client.
You can find more details under here.