I ran into a similar problem and only deleting them manually fixed it.
It is mostly because of exporting and re-importing the database.
Use FTP to restore the original functions.php file from your theme files.
Then investigate the changes in the functions.php file you made previously to fix the error. There should be something around ” and ‘
I use WP Cleanup and it works really well for cleaning up dead links. @leejosepho has the answer for you
