No Connection to Octoprint via Browser

What is the problem?
Last week my octoprint worked fine, i changed nothing.
Today a wanted to start a print, i called the Url i uses everytime.
It opens a site with troubleshooting options.
I can connect to octoprint via putty and it shows me the url i used everytime.

What did you already try to solve it?
Restarted rapsberry pi
Logs (syslog, dmesg, ... no logs, no support)
There is no up to date logfile.
Additional information about your network (Hardware you are trying to connect to, hardware you are trying to connect from, router, access point, used operating systems, ...)
Connected to a Fritz box via Lan cable. ITs the same Network as my pc.