Notifications
The following table represents all the possible notifications that may appear in the Notification Center while working with Zend Server.
| Name | Description | 
| Component not installed | This notification is displayed when Zend Server identifies a Zend component that is not installed, and that should be according to the database blueprint. | 
| Component not loaded | This notification is displayed when Zend Server identifies a Zend component that is not loaded, and that should be according to the database blueprint. | 
| Database connection restored | This notification is displayed when Zend Server has restored a database connection for a server. | 
| Failed to add server | This notification is displayed when Zend Server failed to add a server to a cluster. | 
| Failed to define | This notification is displayed when Zend Server failed to define an application. | 
| Failed to deploy | This notification is displayed when Zend Server failed to deploy an application. | 
| Failed to deploy library | This notification is displayed when Zend Server failed to deploy a library. | 
| Failed to disable server | This notification is displayed when Zend Server failed to disable a server in a cluster. | 
| Failed to enable server | This notification is displayed when Zend Server failed to enable a server in a cluster. | 
| Failed to force remove server | This notification is displayed when Zend Server failed to force remove a server from a cluster. | 
| Failed to health check | This notification is displayed when Zend Server failed to health check an application. | 
| Failed to redeploy | This notification is displayed when Zend Server failed to redeploy an application. | 
| Failed to remove | This notification is displayed when Zend Server failed to remove an application. | 
| Failed to remove library | This notification is displayed when Zend Server failed to remove a library. | 
| Failed to remove server | This notification is displayed when Zend Server failed to remove a server to a cluster. | 
| Failed to rollback | This notification is displayed when Zend Server failed to roll back an application. | 
| Failed to update | This notification is displayed when Zend Server failed to update an application | 
| Failed to update library default version | This notification is displayed when Zend Server failed to set a library as the default library version. | 
| Graceful shutdown failed | This notification is displayed if Zend Server fails to perform a graceful shutdown while scaling down a cluster. | 
| Invalid license | This notification is displayed when the Zend Server license you are currently using has expired or is invalid. | 
| Job Queue reached a high concurrency level | This notification is displayed when Zend Job Queue reaches its defined high concurrency level. | 
| Library Update Available | This notification is displayed when Zend Server identifies the availability of an update for a deployed library. | 
| License is about to expire | This notification is displayed when a Zend Server license is about to expire | 
| Mail server settings are needed | This notification is displayed when Zend Server attempts to send an email, and mail settings are not defined. | 
| Mismatched component directive | This notification is displayed when Zend Server identifies a mismatch in the value of a Zend component directive, compared with the blueprint saved on the database. | 
| Mismatched extension directive | This notification is displayed when Zend Server identifies a mismatch in the value of a PHP extension directive, compared with the blueprint saved on the database. | 
| Missing Virtual Host | This notification is displayed when Zend Server identifies a virtual host is missing. | 
| Modified Virtual Host | This notification is displayed when Zend Server identifies an existing virtual host has been edited. | 
| Offline daemon | This notification is displayed when one of the Zend Server daemons is not running (ZDD, ZQD, SCD, JB and Monitor Node). | 
| Offline server | This notification is displayed when one of the servers in the cluster goes offline. | 
| PHP extension not loaded | This notification is displayed when Zend Server identifies a PHP extension that is not loaded, and that should be according to the database blueprint | 
| PHP extension not installed | This notification is displayed when Zend Server identifies a PHP extension that is not installed, and that should be according to the database blueprint. | 
| Restart required | This notification is displayed when Zend Server requires a restart to apply changes. | 
| Session Clustering is disabled | This notification is displayed when Session Clustering is disabled since the PHP session directive 'session.save_handler' is set to 'files' and not 'cluster'. | 
| Session Clustering failed to locate backup servers | This notification is displayed if the Session Clustering daemon fails to store sessions on a backup server. | 
| Sessions may not be tracked | This notification is displayed when Session Clustering is activated without the | 
| Web server configuration error | This notification is displayed when Zend Server identifies a Web server configuration error (e.g., syntax error in Web server configuration file). | 
| Web server is not responding | This notification is displayed when Zend Server is not responding (e.g., if Apache is down). | 
| You have reached the maximum amount of allowed servers for this license | This notification is displayed when the server you added to a cluster exceeded the amount of servers allowed in the license. | 
| Your license does not include support | This notification is displayed once your 1-year support period expires. | 
| Zend Server daemon is offline | This notification is displayed when a system failure occurs and the Zend Server daemon fails to report. | 
 
                            
                        


