Event 142 Report server windows service

Hi Guys,

Please check the following issue.

Schedules, events, and subscriptions processing may be delayed because processing queue reached the maximum item count = 24. Items currently being processed: 
#0, Microsoft.ReportingServices.Library.NotificationQueueItem
#1, Microsoft.ReportingServices.Library.NotificationQueueItem
#2, Microsoft.ReportingServices.Library.NotificationQueueItem
#3, Microsoft.ReportingServices.Library.NotificationQueueItem
#4, Microsoft.ReportingServices.Library.NotificationQueueItem
#5, Microsoft.ReportingServices.Library.NotificationQueueItem
#6, Microsoft.ReportingServices.Library.NotificationQueueItem
#7, Microsoft.ReportingServices.Library.NotificationQueueItem
#8, Microsoft.ReportingServices.Library.NotificationQueueItem
#9, Microsoft.ReportingServices.Library.NotificationQueueItem
#10, Microsoft.ReportingServices.Library.NotificationQueueItem
#11, Microsoft.ReportingServices.Library.NotificationQueueItem
#12, Microsoft.ReportingServices.Library.NotificationQueueItem
#13, Microsoft.ReportingServices.Library.NotificationQueueItem
#14, Microsoft.ReportingServices.Library.NotificationQueueItem
#15, Microsoft.ReportingServices.Library.NotificationQueueItem
#16, Microsoft.ReportingServices.Library.NotificationQueueItem
#17, Microsoft.ReportingServices.Library.NotificationQueueItem
#18, Microsoft.ReportingServices.Library.NotificationQueueItem
#19, Microsoft.ReportingServices.Library.NotificationQueueItem
#20, Microsoft.ReportingServices.Library.NotificationQueueItem
#21, Microsoft.ReportingServices.Library.NotificationQueueItem
#22, Microsoft.ReportingServices.Library.NotificationQueueItem
#23, Microsoft.ReportingServices.Library.NotificationQueueItem." 

Please provide solution how to resolve it, is the above issue related to SQL DBA, i haven't any idea about SSRS.

Thanks

DBA