NC11 + Keeweb 0.3.0 → Blank screen

Fresh installation of NC 11.0.0 on Ubuntu Server 16.04 x64 with ISPconfig 3.1.1.p1 and PHP 7.08
Client: Firefox 50.1.0 on Linux Mint 18

Error message:

Load denied by X-Frame-Options: does not permit framing

Does someone has the error too?
How can i fix it?

Thank you!

Here the solution

Seems to work now.