I struggled since some days to get any results from the advanced search page:
https://project-gc.com/Home/Search#AdvancedSearch
My intention is to search caches in a certain area (using the Location field (Region, County, Country)) and with certain word in the cache description (using the cache description field).
Example:
Location= Nordrhein-Westfalen
Cache description= Trail
It always returns an "UNKNOWN ERROR".
After trying several things I changed the search mode for the location field from "Extended" to "Exact" and now its working.
This looks a bit like a bug or I don't understand how the "Extended" mode works.