RDP Session via a F5 Remote Portal

Hi guys,

i'am trying to Setup a remote Portal via a virt. Server on the F6 APM. Login via Multifactor and assign ressources like OWA etc. are working well. Now added a ressource to use assign RDP Sessions via the Portal. I'am able to start the Session but while it try to connect (passing the internal FW's Looks fine) i'am getting the following error. The session can not be completed because off authentication is not activated. If i'am trying internally, not thorugh the F5, the RDP Session starts to the same Windows Server. SSO is actviatet and working well via OWA. I'am using Version BIG-IP 13.0.0 Build 2.153.1671. Any Ideas what i'am doing wrong?

Thanks a regards Martin