Plugin return null

I don’t understand what is wrong with it
php 5.4.41
wordpress 4.3 (also 4.3.2 4.4.1 is same)
plugins versions 1.2.4 (1.2.5 was tested)

when I send for example correct request https://votarist.cloudsite.ir/wp-json/posts nothing appear but in wrong request like https://votarist.cloudsite.ir/wp-json/posts?filtertag=wrong shows “[]” or bad command like https://votarist.cloudsite.ir/wp-json/json/posts?filtertag=intro return [{“code”:”json_no_route”,”message”:”No route was found matching the URL and request method”}]

I don’t understand what is wrong with it
php 5.4.41
wordpress 4.3 (also 4.3.2 4.4.1 is same)
plugins versions 1.2.4 (1.2.5 was tested)

when I send for example correct request https://votarist.cloudsite.ir/wp-json/posts nothing appear but in wrong request like https://votarist.cloudsite.ir/wp-json/posts?filtertag=wrong shows “[]” or bad command like https://votarist.cloudsite.ir/wp-json/json/posts?filtertag=intro return [{“code”:”json_no_route”,”message”:”No route was found matching the URL and request method”}]