This most likely is somehow related I would guess. 

Are you able to set up a directory watch or FTP watch in the old fashioned way (e.g., Notifications(classic), Publications)? If you set up the publications you might see some more information in the specific publication logs (logs>core>current>publishers>dirwatch.log).

It’s also possible some ports are closed. You can see more info on ports here: https://docs.safe.com/fme/html/FME-Flow/ReferenceManual/FME-Flow-Ports.htm
 

Setting up a directory watch or FTP watch in the old pattern that will give you solution.

Thanks a lot for all your answers. I think indeed the issue is most likely due to the Architektur and how things are set up.

In the end I was able to configure a Trigger watching an sFTP but after that it was not possible to lunche a workbench.

On the setup I am working with the number of parallel running workbenches is limited to 1. Not understanding what really happens behind the scene in a Automation but I think that this is one of the factors that makes thins not working.

The solution in the end was to avoid Automation and run different workbenches that are launched with a schedule. Not too elegant but it works.

Where there’s a will, there’s a way.

I’ll be honest, my experience of FTP and directory watch has always been a bit hit and miss. Sometimes things fail to trigger and on the flip side I’d had the case where ALL files in an FTP have caused simultaneous triggers - that was a real mess.