Hi Ayberk,

Could you verify if you have an automatic redirect configured in your index.html page, for example like the one described in this section of the SAML docs? If so, this is most likely the problem. Whenever the module tries to generate a PDF document from a page, it automatically gets redirected to the SSO login page, resulting in the error you described. 

To solve this, you could try out the steps described in the info box in the same section of the SAML module documentation, starting with "If you want to redirect users who have not yet signed in automatically ..", or for example move the (automatic) redirect to the login page only.

Hope this helps! If you're still stuck after trying the steps above, please create a ticket with Mendix support with a test project attached so we can take a look with you.