as far as my best knowledge
While Starting the webMethods Integration Server Make sure that the external database to which Integration Server connects is available before staring Integration Server. If the database is unavailable at Integration Server startup, some components, such as the scheduler, will not be initialized and will not work properly.
Integration Server needs to perform system tasks periodically, such as expiring sessions. Integration Server schedules these tasks automatically.in such situations you are getting exceptions .
To view the scheduled system tasks
- Open the Integration Server Administrator if it is not already open.
- In the Server menu of the Navigation panel, click Scheduler.
- Click View system tasks.
The server displays the View System Tasks screen. It lists the names of each scheduled
task, the next date and time the server is to execute the task, and how often (Interval)
the server is to execute the task.
Note: The View System Tasks screen shows the tasks for local server only; if you are running a group of servers connected to the same database, you will not see the system tasks for other servers connected to the database By default, Integration Server uses the host name to identify itself while scheduling tasks.
If you are using in cluster single machine you need to set following property .
Specifies a unique logical name to identify Integration Server instances in a cluster hosted on a single machine. By default, Integration Server uses the host name to identify itself while scheduling tasks. However, when a cluster of Integration Servers are hosted on a single machine, the host name itself cannot uniquely identify the individual Integration Server instances. In such cases, use the watt.server.scheduler.logical.hostname property to specify a unique logical name to identify individual Integration Server instances.The default value for this parameter is the host name.
Keep the following points in mind when setting the watt.server.scheduler.logical.hostname property:
Set this property only if you are running multiple Integration Servers in a cluster on a single machine.
Set this property on each Integration Server instance in the cluster before scheduling any tasks
if you are still getting the error please share IS Logs .