We have like 6 sites in Multi Site available. Just installed the Multi Sites Articles sharing and wanted to select an article from 1 site that was not listed under the option Parameters -> Site. All other sites I can select I'm just missing 2 sites.

Any ideas?

Does all the website are in status "confirmed" in JMS ?

When I check site manager I see behind every domain confirmed

Found it.
If you go to the global configuration -> site -> site name = empty you wont been able to see it in Multi Sites Articles sharing. I thought the article sharing was done based on siteID?

In some cases you don't want to see the site name popup in plain text on the site if you have a logo placed on the top.

YES the article sharing is based on the site ID.
Based on the site ID, it retreives the configuration of the websites that is located in the directory described in JMS.
So I don't understand the relationship between the site name present in the global configuration and the site id.

So I don't understand the solution and the relationship between the list.
I need that you give more description on the scenarion to allow me reproduce it and better understand your description.
Screenshot may help us understand the case.