If you're seeing this notification at the top of the credential page (under Flexmls IDX>Flexmls IDX in WordPress), your web host is using nginx as a web server for WordPress. nginx works differently than the Apache web server. Making changes to the Permalink Structure needs to be configured within the nginx configuration file.
Click on the "Required nginx Configuration", here you'll find the nginx permalink structure rules for the Flexmls IDX WordPress plugin listing pages (search results and listing detail pages). Click the blue Copy button.
Add these rules to your nginx server block configuration file (usually located at /etc/nginx/sites-available/your-site or similar).
Need Help?
If you're not comfortable editing nginx configuration files, please contact your website hosting provider or system administrator for assistance. They can help you add these rewrite rules to your nginx configuration.