URL RewriteRule doesn’t work when using WP Database Participants in my WordPress website

I’d try changing the order of your rules. Once the default WP rules run, your URL will be rewritten and your last rule won’t work.

SetEnv no-gzip dont-vary
RewriteEngine On
RewriteRule ^produse/piese-schimb-utilaje-agricole/([0-9]+)/?$ ^produse/piese-schimb-utilaje-agricole/?listpage=$1&search_field=none&value=&operator=LIKE&sortBy=denumire&ascdesc=asc&submit=&sortstring=denumire&orderstring=asc#participants-list [NC,L]

# Turn mod_rewrite on
RewriteEngine On
RewriteBase /

RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]