Zyxel NAS 542

Hej guys, hope I get some help here. I got a NAS 542 which is setup for home network use. I got on all devices access to the NAS. the problem iam facing now is that iam not able to reach out to my NAS over the internet. Also weird is that I cannot ping any outside website from the build in Ping function of the NAS. Fritzbox Router has UPnP enabled and the NAS has the rights to perform port forwarding on its own. Nevertheless says the Zyxel NAS that it can't see any UPnP supported Router in my network.

Maybe some of You guys has an idea.

• I checked for Mac address filtering

• Checked for Whitelist or Blacklist or anything

Ty in advance.