I found what was the issue.

There was indeed something happening in the audit portal. Each attempt of the page was adding a line in this page :

I added the role of the application /terminalsocket to %All and now the error is gone. I have no clue why this happened though, your package didn't seems to change this kind of parameters (Or maybe I missed it).

In any case, thank you for your help !

I tried these operations.

There was no /terminalsocket indeed in the web session portal before I launched a new session. However, this session does not disappear when I close the page. It even create another session for each attempt it make, so every 10 seconds. After waiting a bit (like 5 - 10 minutes), some begin to disapear.

It doesn't show more than the error message saying it can't connect, but it seems it use the 4.9.5 version, I found this in the index.js source file :

I notice the user is UnknownUser. Could this have an impact ?

Sorry for the late response, I didn't saw the notification.

Unfortunatly, the update didn't solve the problem. Is there a something particular I need to do beside importing the new package (still in the user namespace ?) ?