[EDIT: we’ve been able to stop some bots that were abusing the Freesound search and now search is working for everyone again. We’re implementing some measures to stop this from happening again.]
Yesterday we had some issues with the search server that were fixed at some point, but last night the issues started again and still persist. We’ll work to fix these as soon as possible and let you know when done. Thanks for your understanding!
Meanwhile you can still to some browsing by navigating user profiles and/or using the random sound feature: https://freesound.org/browse/random/ 🙂