Hello,
Thank you for contacting Rank Math today.
You can head over to Rank Math > Dashboard and enable the 404 Monitor.
Have a look at this screenshot for your reference – 
Further, you can head over to Rank Math > General settings > 404 Monitor and enable the Advanced mode which will then log the referrer of the 404 errors.
Here’s a detailed knowledge base article on 404 Monitor Module – https://rankmath.com/kb/monitor-404-errors/
Looking forward to helping you. Thank you.
No Sir, My 404 404 Monitor MODULES not activate. it shows processing but not activate
and aslo i m not able to connect my rank math account with the plugin
Hello,
If the Module is not enabled, please check if you are using a Firewall, as it may prevent saving the changes.
If you are using a Firewall, please whitelist these routes:
/wp-json/rankmath/v1/updateMeta
/wp-json/rankmath/v1/saveModule
Whitelisting the route should fix the issue.
You can check this link for more information:
https://rankmath.com/kb/meta-data-not-saving/#firewall
For the connection, go to WordPress Dashboard > Settings > General, and make sure that the “WordPress Address” and “Site Address” have the same setup.
Meaning both URLs have the same exact protocols. They should be matching and not have a mismatch.

I hope this helps. Looking forward to helping you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.