after install Rank Math & display Error 404

Hello,

I’m sorry to hear that you’re facing issues with the Rank Math SEO plugin causing 404 errors on your website. This could be due to a conflict or misconfiguration. To troubleshoot this, please follow these steps:

1. Check Plugin Conflict: Deactivate all other plugins except Rank Math and see if the issue persists. If the problem goes away, reactivate the plugins one by one to identify the conflicting plugin.

2. Check Theme Compatibility: Temporarily switch to a default WordPress theme like Twenty Twenty-One to see if the issue is related to your current theme.

3. Review Rank Math Settings: Ensure that the 404 Monitor module in Rank Math is correctly configured. You can refer to our guide on how to set up and monitor 404 errors using Rank Math for detailed instructions.

If the issue persists after following these steps, please reply here, and a human agent from the Rank Math Support team will assist you further.

Thank you for your understanding and patience.

Sources:
How to Setup Rank Math SEO Plugin Properly
How to Monitor 404 Errors with Rank Math SEO Plugin
How to Find Out Where 404 Errors Are Coming From » Rank Math
Solving Redirection Issues Using Rank Math SEO Plugin » Rank Math

Hello,

For troubleshooting, please check this option in Rank Math > General Settings > Links as it modifies your URLs:
https://rankmath.com/kb/general-settings/#strip-category-base

Let us know how this goes.