Hello,
We are using SEN on prem version. We recorded training videos and added context them in desktop assistant sub-group folder. We could generate and start desktop assistant too. As authors, we are using one account for login to producer and manager. (Since it's on prem, our username starts with local\ ) But we couldn't make our end-users access to desktop assistant. As I researched the sources and guides,

We need to use these links. When trying to opening authoring and published view links, above a pop-up asking for username and password displayed but when we input our username and password we use for login to manager, the login failed. (We can login to manager with these credentials by the way) We got that error:

When trying to open last link which is desktop assistant preview, we got this error:

Normally, this link should have been accessible and triggered download process of a dnt file. In end users' computers, there is only desktop assistant installed. We also tried to open that link from someone's computer with both desktop assistant and producer installed but it didn't work. Authors from their own computers was able to access desktop assistant preview link and download dnt file. How end users or some other authors can start the desktop assistant via desktop assistant URL?
Kind regards.