You mean via using the Find Similar feature?

That's handled by a completely different system from us, IQDB. It's a thrid-party-developed engine used by several websites. It culls info from the participating sites to build it's DB and results.

If you're having issue with just one site using this feature, it's usually a problem with the site in question. If IQDB is actually having problems, it would affect all search results, not just the ones from a single site.

Konachan (Shuugo) used to have the IQDB system hosted on the same physical server as Konachan itself. However, due to resource issues discovered during the previous server move (and all the attempts to optimize the site), IQDB was transferred to Imouto. They have a MUCH beefier server than we do.

I suggest you browse Danbooru directly. I'm pretty sure you'll find Dan instelf to be having problems. Otherwise, we can't do much since we no longer have physical custody of the IQBD system. (At most, the main IQBD URL still uses one of Shuugo's sub-domains.)

EDIT:
And I find that imouto (and therefore IQDB) is down right after I posted this ^_^;