Fatal Error message on scan

Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 31457280 bytes) in /services/webpages/a/r/domain.com/public/wp-content/plugins/wordfence/lib/wfConfig.php on line 531

I’ve tried deactivating, using “Delete WF tables and data on deactivation”, deleting and reinstalling – same error.

Before you say it’s the server, I’ve 50 domains hosted on the same server, about 20 using WP and this is the only one that is giving this message. My last successful manual can on this domain was about 2 weeks ago.

Please advise.