Your Atelier server connection information is stored in Eclipse's secure storage file. The secure storage file is shared among different workspaces created in the same Eclipse client. You can see the location of this file in your Eclipse preferences under General > Security > Secure Storage > Contents > Storage location.

The location of the secure storage file depends on the directory in which Eclipse was installed. If you want a second install with an independent list of server connections, you will need to install the second Eclipse client in a new directory.

What exactly have you tried so far? What version of Atelier are you using? What version of Caché/Ensemble/HealthShare?

I would suggest contacting the WRC (by emailing support@intersystems.com or calling 617-621-0700) to get further help on this. A Support advisor will be able to give you one-on-one help to get to the root of the problem on your system.

Currently (with Atelier 1.1.391), opening and editing class, routine and csp files are supported. The BPL and DTL graphical editors are also fully supported. Beyond that, more inclusive Ensemble support is targeted for Atelier 2.0. Keep an eye on announcements in the Atelier group in the Developer Community and Atelier release notes for information about upcoming versions.

This has been reported and corrected (development code CDS2960). This required a server-side change that appears in 2017.1.3, 2017.1.4 and 2017.2.2. Can you send your Caché/Ensemble/HealthShare version string so that I can confirm you do not already have a version with this fix? You can get that by clicking the About link in the top-left of the System Management Portal.

This should be the web server port. The PKIX error usually indicates an issue with HTTPS (such as the web server expecting HTTPS but receiving an HTTP request). The "Connection refused" message could mean that the path for the REST requests made by Atelier are not being properly served to the CSP Gateway.

As Francisco mentioned, you can give this a try with the private Apache web server (by default listening on port 57772) which should be able to serve the REST requests from Atelier out of the box. That will give us a baseline of whether you can connect your Atelier client to the server.

I would suggest opening a WRC case so that a Support advisor can get specifics about the web server you are using and how that is configured.

If I understand correctly, you are looking for the DTL graphical editor within Atelier? To do this you will want to open the DTL class code, then right-click in the editor and select "Open diagram editor". You can find a previous post with more detail here:

https://community.intersystems.com/post/how-edit-business-process-and-data-transformation-files-atelier