Hybris Marketing Custom Fields and Logic Error

Dear Experts,

I'm working in an Hybris Marketing on-prem (1702) scenario. When I try to add a new field via the app "Custom Fields & Logic" I get the Error Message:

My User has a copy of the role SAP_CEI_EXT_CFD assigned and I checked in /IWFND/MAINT_SERVICES that the service APS_CUSTOM_FIELD_MAINTENANCE_SRV

is active.

Does anybody know how to solve this issue?

Regards

Tobias