Fresh Win11 install, fresh Office365 install, Onedrive backup no connection to OneDrive-service

Hi community,

got a new laptop with win11. fresh installation, 

Installed Office 365 (family license) as first package.

No firewall/Antivirus other backup software installed.

Onedrive says it´s connected. But if I start to select folders (documents/pictures) to automatically backup, the feedback is

"Problem with connecting to the onedrive-service"

File length or file names can´t be the issue, same error if folders are empty (fresh installation)

No matter if I´m connected through my router (LAN/WLAN), hotspot on my mobile phone, neighbour´s network.

Tried all resetting options Microsoft and web search is giving. No other result.

Can anyone help me? 

trying to reach the support leads to "this support is currently not available"