gpodder.net search works for me. SoundCloud does appear broken.
SoundCloud returns a 401 error (unauthorized). It looks like they overhauled the API/ditched the free access key. That seems to be the general tendency with popular single point of information sources these days.
If there were two or three leading OSS apps,I might spend time sending good bug reports to one of them. When there are over a dozen, and most of them fail in the same way for me ... it's past time for a shakeout in the population of apps.