Openhab2 and myopenhab/Cloud connector - which ports have to be opened from the web?


I tried to Install openhab 2 and to connect it via myopenhab with Alexa.
Openhab runs on a Raspberry Pi that is not accessible direktly from the web. Publishing items to the Cloud works but whenever i try to do some changes via myopenhab (for example deleting Item links from Things) it returns 404 not found Messages in paperui GUI.
Also tagged items are not found by Alexa (Nothing is found here).
I think the problem is that myopenhab needs to access my Raspberry behind the Router to work. Only forwarding port 8080 did not Help.
Which ports / Services have to be forwarded to the Raspberry in my Router to make myopenhab work and to make Alexa to find the items tagged with Lighting, switchable and so on?
Any other hints what I might have forgotten?

Thanks for your Help!

I have no port opened and can switch my items via myopenhab!
However, I’m using a “normal” Unto do that and not the admin UI (Paper6).
Additionally I have configured myopenhab in PaperUI for Notification and RemoteAccess, and I have all Items which I want to access from the internet selectedto be exposed.