You have to import the MxModelReflection module too.
Did you already also imported the MxModelReflection module? Double check the other modules you need when using the SAML module. See the documentation of the SAML module.
Regards,
Ronald
It looks like you’ve not installed the Mx Model Reflection module from the Marketplace.
https://docs.mendix.com/appstore/modules/saml#1-4-dependencies