Which version of LW are you using?
Sometimes if you search same terms too many times, the ultrapeers you are connected to stop reacting.

Same thing happens to me now & again. I don't really bother too much about it. Though I might restart my LW occasionally & try again later.

However, it might also be the ultrapeers you are connected to. I'd suggest going to View menu Show/hide connections. Select the one you've been connected to longest, press Remove. Wait a few minutes for your connection to stabilise. Sometimes it takes longer than other times to get a new stable ultrapeer.

Ultrapeers come in all shapes & forms. Some cheat their way to become ultrapeers but do not behave well as ultrapeers. And then there's some 'dud' ultrapeers that do not respond at all to search messages. And then there's some spam ultrapeers. The last two being the worst.

(Yes I know LW support pages suggest reinstalling to fix many types of problems. I think for most people it's wasting their time. They even suggest removing LW in the incorrect way via using the add/remove control panel. The installer they have used for past 4 years is different & has its own uninstaller. And using the LW support pages' removal advice can cause problems not removing all registry bits.)