The error may be due to conflict with a plugin or theme. Make sure you are up to date with the latest versions of your theme, plugins, and WordPress. Newer versions of plugins and themes can already contain a fix for the issue you are experiencing. After updating, check if the issue persists. If persists, log in on your WordPress website. Deactivate all plugins one by one. Switch your theme to a standard theme like Twenty Fourteen. Test for the issue again. Does it still occur? If you installed Yoast SEO plugin, deactivate the plugin and check. You can use the Health Check & Troubleshooting plugin. This plugin allows you to run a conflict check without affecting normal visitors to your site. In WordPress, on the left-hand side, you will see a menu. In that menu, click on ‘Tools ’. The ‘Tools’ menu will expand providing you with additional options. Click on ‘Site Health’.