Problem searching only by taxonomy

Hi,

I am quite new to WordPress and Search and Filter plugin. I am having some problems getting the search working correctly for custom taxonomies.

I am trying to make a search page to search only pages with text input and checkboxes for filtering based on custom taxonomies. Below is an example search code I used for testing:

[searchandfilter fields="search,tax1" headings="Keyword,MyTax" types=",checkbox" hide_empty="0,0" operators="AND" post_types="page" submit_label="Search"]

I set some keyword for search (e.g. keyword “a” that matches all my pages) and select the wanted taxonomy values (e.g. “value1”), I get all of my pages matching the keyword “a” and having the selected taxonomy values. The search query generated is http://<domain>/?s=a&post_types=page&tax1=value1

The problem is that if I leave the keyword unset and select only the wanted taxonomy values, I get “That page can’t be found.”. The search query generated is http://<domain>/tax1/value1/?post_types=page

How can I get the search working so that user can also search by selecting wanted taxonomy values instead of giving a search keyword?

https://ww.wp.xz.cn/plugins/search-filter/