Can't update HASSIO, can't install addon, https not working. 500 Server Error: Internal Server Error

Since few hours I have the problem that my outside of the LAN access does not work, when I try to update or download any HASSIO addon I recieve the below error.

ERROR (SyncWorker_9) [hassio.docker.interface] Can’t install hassioaddons/nginxproxymanager-amd64:0.2.1 -> 500 Server Error: Internal Server Error (“Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io: no such host”).

Trying to figure out what is happening, but I am a bit lost. Any clue?

Everything else in my LAn seems to work fine