Error 500: Create/Update Services

Every time I try to update, change or create a new Service an error 500 occurs and I get stuck. It tries to load the URL: https://inkatari.cl/wp-admin/post.php and shows an error 500 saying “This page isn’t working,
The site inkatari.cl can’t proccess the request.
HTTP ERROR 500″

I have tried everything from changing memory limits to renaming the htaccess and other things but it only happens with this plugin when trying to create or update a service.

I need to know if this problem can be solved before buying please.

Thanks you!

Sergio