Webservice consumption

Hi all experts, Maybe someone can help me with the following.

On my server, there is a process modelled, that can be launched with WSNavigator.

I configured all to be able to search my webservice in Visual Composer. The webservice is available for selection. When I select the webservice to start the BPM process and test it, VC replies that it cannot start the webservice and I need to contact the system admin.

How can I fix this?

Thanks in advance, Martijn.