Hassio app/web interface not accesibale after update

Dear all,
after upgrading to the latest software version (through the web interface), my hassio is not accesibale via web interace or app any longer. I can still connect via ssh and the observer says:

Supervisor: Connected
Supported: Supported
Healthy: Healthy

Is there anything I am overlooking or I could do?

Thank you for your help!