The application pool is recycled too frequently because its virtual or physical memory consumption reached the configured limit. This could be indicative of a memory leak inside the code which the application pool is executing.
There is a memory leak inside the code which the application pool is executing.
The physical or virtual memory limit is set too low.
To check or configure application pool limit settings by using IIS Manager:
Click Start, click Control Panel, and then click Administrative Tools.
Right-click Internet Information Services (IIS) Manager and select Run as administrator.
In the Connections pane on the left, expand the computer, then select the Application Pools folder underneath the computer name.
In Features View, select the application pool. In the Actions pane, select Advanced Settings.
Check or configure the settings for application pool limits under the appropriate section(s).
Note: Because this is a manual reset monitor, after fixing the problem you will need to reset the state of this monitor in health explorer. You can do this by right clicking on the monitor and selecting the "Reset Health" menu item. Unless you manually reset the monitor, it will not switch to healthy state.