I had the same kind of issue when I upgraded our app from 9.18.4 to 9.24.1
I was able to resolve it by updating the libraries.
Here is the list of libraries used by default in mendix 9.24.1:
I created a new project in mendix9.24.1, copy pasted those libraries in my real project , and removed old (duplicated) ones.
Hope that helps.
Updating the SAML module to the latest version is what worked for me.
Hi all! The solution that worked for me was renaming the session cookie. After Mendix version 9.20 cookie was renamed to "XASSESSIONID”, before that there was a "Host_” prefix. You can just open your project in Eclipse IDE and using 'Search’ find where you use prefix "Host_” (unfortunately, I don't remember the full name). For me it was in LoginUser.java file. Then rename it to "XASSESSIONID”, save, build on Eclipse and run on Mendix.
Hope this helps!