Error in loading FreePBX dashboard

/var/log/asterisk/freepbx.log may have some guidance.

The overview panel checks various subsystems and perhaps one of the tests is blocking. You can look through /var/www/html/admin/modules/dashboard/sections/Overview.class.php to see whether anything catches your attention. Do you have the mailq program installed? That’s the only direct system call in the script, and might be the offender.