clicking to save settings directs me to 404 page

I have pages and i wanted to use this as replacement for nrelate. Activating the plugin doesn’t do anything. I went through setup clicking the save button in the end get’s me to a 404 page. It doesn’t seem like settings are remembered. I also can not set it to use titles. the options are just greyed out in the menu. example: https://drive.google.com/file/d/0B2uTW36AgbQzSGZoQUZkZjVaX0E/view?usp=sharing

https://www.ads-software.com/plugins/yet-another-related-posts-plugin/