I have downloaded Mendix 5.15.0 and the company expenses project from appstore. It was working fine for 1 or 2 days and then this issue happen. Once I log-in the system redirects me back to the login page. No errors or messages that I can use for troubleshooting, I need any rapid fix because I have POC demo tomorrow morning. Edit: I found that issue is raised only in case of there is any of the add-on widgets from the app store in my forms and Once I remove them all ,the issue disappears. Thanks in advance.
I've noticed a similar issue but it occured in older modeler versions as well. Changing my runtime port fixed this for a while. This could be a workaround for your Demo.