404未找到AJAX REQUEST GT

i have some problem with this request :

When i make a request with value of 2017

http://01tm.com/wp-content/themes/voetvolk_2017/core/process/aru.php?request=&target=arrange_url&method=method_target&year=2017&month=06&project=all&country=all&tour=all

No problem,

But when i make a request with value 2018 i got en error 404 on GET. But in the developer tools in tab Sources i have an output correct.

http://01tm.com/wp-content/themes/voetvolk_2017/core/process/aru.php?request=&target=arrange_url&method=method_target&year=2018&month=06&project=all&country=all&tour=all

Thx for reply

I fix it with :

include_once('../../../../../wp-blog-header.php');

header("HTTP/1.1 200 OK");