How to Change permalink Redirect /%post_name%.html/ to /%post_name%/ ?

Hello,

Thank you for contacting Rank Math and bringing your concern to our attention.

If you wanted to remove the .html from your posts, you can update it on your WordPress dashboard > Settings > Permalinks. WordPress should automatically redirect your old URL structure to the new ones.

However, if the redirect is not working upon changing the permalinks, you can try to use this regex:

Source: ([^/.]+).html$
Type: Regex
Destination: https://yourdomain.com/$1

Please update the destination with your actual domain name.

I hope that helps.

Thank you.