incase you unistall the word fence plugin
just delete .usr.ini file its in hidden mode in your WordPress root directory.
Changing an account’s username or transferring an account to a server with a different home path will not update customizations made to the .user.ini files located in the wordpress install home folder. This will cause WordFence to access wordfence-waf.php at an incorrect location.
change the directory path that getting not found to correct
usr.ini file contains
; Wordfence WAF auto_prepend_file = '/home/oldpath/public_html/wordfence-waf.php' ; END Wordfence WAF
my case in linux
is used ls -a to show hidden file or .files
After cloning into a staging site or migrating your website to another host, the
.user.ini still contains a link to the absolute path of the original web site’s