Thanks for reaching out. We’ve been investigating these reports and now think we have a cause and a solution.
One thing to note, that if you see an error in your logs about running out of memory, it may not be the same issue. It might be a case of needing to allocate more memory to PHP. PHP memory is cumulative. That means the amount set in php.ini is shared between all your plugins, your theme, and WordPress, plus any other non-WordPress apps you have installed in the site folder. We recommend changing it to 256M and upgrading to PHP 7 or above, which introduced better memory handling. If that doesn’t help, please try one of the other solutions mentioned here.
What we found is that on some sites the emailedIssuesList row in the wfconfig table had became too large from recording hashes of previously emailed scan issues. Reinstalling Wordfence fresh (where the data and database tables are removed) was fixing the issue but this lets us know exactly where the problem was.
There are 2 ways of fixing this.
1. If you are comfortable using MySQL queries you can issue this command using PHPMyAdmin in your hosting control panel:
delete from wp_wfConfig where name = ’emailedIssuesList’;
2. If you are not comfortable with running queries do this:
Remove and reset Wordfence, using the Wordfence Assistant plugin to remove all tables and data and then reinstall the plugin.
We are looking at a solution to prevent it from happening again and hopefully will include it in the next release.
Thanks always for being patient as we worked diligently to solve this for our customers. Thanks as well for reaching out and providing valuable information to help us solve it. Let us know if this solves it for you.