Can't ad anything to Playlist

My web UI behaves strangely. I can’t ad anything to the playlist, although i can play files from a usb drive. The radio stations can’t be played. When I activate the Library and switch to it just shows “LOADING”. I tried several reboots and I even switched it off and disconnected the power strip.

This is what I configured up to now:
I installed the standard Image and everything worked fine so far.
So I configured my RPi2 to act as a adhoc wifi-station for playing music form my iPhone via Airplay without connecting it to a network, which works great.
After accidentally pulling the power strip and a reboot I changed some settings in the web UI. After that I recognized the strange behavior.

Any ideas what might went wrong?

Thanks for your help.

My setup:
-IQ-Audio DigiAMP+
-Netgear WiFi-stick
-Volumio Version 1.55