ERROR: The specified [RECORD_TYPE] related action does not exist or you do not have permission to view it

Hello,
this question is connected to this.

I have created a related type with a related action that calls a process model; i have a column in the list that start this process model.

The record type has this security:

• <ADMIN user group>: Administrator
• <ALL USERS>: Viewer

The process model has this security:

• <ADMIN user group>: Administrator
• <ALL USERS>: Initiator

The integration service called by the process model has this security:

• <ADMIN user group>: Administrator
• <ALL USERS>: Viewer

Please give me some hints.

Thanks in advance.
Marco