Issue
When running any drush command, as drush status, you are getting an error as the following one
PHP Fatal error: Cannot redeclare dd() (previously declared in /usr/local/drush8/vendor/symfony/var-dumper/Resources/functions/dump.php:35) in /mnt/www/html/****/docroot/sites/all/modules/contrib/devel/devel.module on line 1769Resolution
This issue might be linked to the fact that you are using an old Devel module version. The fix from this issue has been committed in the 7.x-1.6 version in the module back in 2018, as you can read in https://www.drupal.org/project/devel/releases/7.x-1.6
Issue #2559061 by dagmar: Fatal error: Cannot redeclare dd().
Disabling or updating the module to its latest version might solve this.