using checkboxes as search keywords

I am trying to get a search form that would bring back results based on the keyword mentioned next to the checkbox. Even though the search bar works fine, when I check any of the checkboxes, it comes back with the message “sorry, no content matched your criteria”.

I did check the meta keywords in the SEO settings for each page that should be coming up and all are there and correct.

Here is the link to the page:
https://www.cbmtest.creativecatgd.com/279-2/

And here is the code:

<form id="search" action="https://cbmtest.creativecatgd.com" method="get"><label for="keywords">Do a custom search</label>
<input id="keywords" name="s" type="text" value="Search" />

<label for="keywords">Or check the boxes for category search</label>
<input name="tag['woodwind']" type="checkbox" value="woodwind" /> Woodwind
<input name="tag['brass]" type="checkbox" value="brass" /> Brass
<input name="tag['strings']" type="checkbox" value="strings" /> Strings
<input name="tag['piano']" type="checkbox" value="piano" /> Piano
<input name="tag['voice']" type="checkbox" value="voice" /> Voice

<input name="tag['classical']" type="checkbox" value="classical" /> Classical
<input name="tag['choral']" type="checkbox" value="choral" /> Choral
<input name="tag['contemporary']" type="checkbox" value="contemporary" /> Contemporary
<input name="tag['jazz']" type="checkbox" value="Jazz" /> Jazz
<input type="submit" value="Go" /></form>

Any suggestions are appreciated!