I'm receiving an error "The website encountered an unexpected error. Please try again later." whenever I try to create a new mailing. If I disable Mosaico and FlexMailer the CiviMail system appears to load correctly, but as soon as I reenable FlexMailer the error returns.
I updated to CiviCRM 5.52.3 earlier today, and also updated the Drupal Views and EU Cookie Consent modules, but otherwise haven't changed anything since this morning when it was working.
I've tried clearing Drupal caches, the Cleanup Caches option in CiviCRM, and deleting all files in sites/default/files/civicrm/templates_c/. So far nothing has made a difference.
I can't see anything in ConfigAndLog with a timestamp matching when I'm trying to create a mailing.