Undefined source

I am unsure in which category my contribution belongs.

Hello, the web frontends often reacts with considerable delay. When attempting to delete the title from the queue, which belong to a source (NAS) which is no longer available, does not happen at first, then the “waiting” and after several minutes it becomes apparent, the front end has crashed.
The web radio continues, the circle pulsates normally. However, there is no access. This changes only when the source (NAS) is available again.
If it is not possible for entries whose state is undefined, delete them from the queue.

Another problem, umlauts in German are not shown.