Hi. In case this helps anyone who searches for this on a later occasion. I was getting the same error. I was running a new blank app that I had set up to test something, so I spent some time scratching my head wondering what was wrong. The Native app wouldn’t start and then I noticed that the message was being generated by an open web page, each time I restarted the app. Then I rebooted my PC and the error went away. The problem was probably due to having run another app before running this one and something not getting cleared down.
Hello
I have the same issue, but only in Chrome, whereas in Firefox it works.
I'm debugging the network calls, and I see that the second POST to /xas returns 401 to Chrome and 200 to Firefox. The only differences I see the Cookies. With Chrome, there are very few Cookies compared to Firefox. As an example, XAS_SESSIONID is not set in Chrome....
I'm still debugging...
I finally managed to solve it and I share my solution.
The problem comes from the fact that Mendix Runtime returns this response header to the first request POST /xas that generates the user session :
Set-Cookie
__Host-XASSESSIONID=4e096fdc-56fa-42b4-8e37-e6c9b807c783; Path=/; Secure; HttpOnly; SameSite=Strict
It is accepted by Firefox but not by Chrome because of the security rules (https://www.ietf.org/archive/id/draft-west-cookie-prefixes-05.txt) that don't accept cookies with prefix __Host on a http connexion.
So the solution was to say to mendix that it runs in http by setting this environment variable
MXRUNTIME_ApplicationRootUrl=http://localhost:8080
That explains why the behaviour is different when you run the app in the Mendix studio (it uses http), and in a Docker image with the MXRUNTIME_ApplicationRootUrl variable.