MailSite Knowledge Base

• ExpressPro 8.x, 9.x

When attempting to load MailSite ExpressPro, the page returns:

You may see the following in the Event Viewer:

Event ID: 1021

The identity of application pool, 'ExpressPro' is invalid. If it remains invalid when the first request for the application pool is processed, the application pool will be disabled. The data field contains the error number

This can occur if the Application Pool for 'ExpressPro' found in IIS has an invalid Identity.

By default the MailSite installer will attempt to create a user called 'MSIISUSER' and assign this account under the Identity tab for the ExpressPro Application pool.

1. Locate the account used for the 'ExpressPro' Application Pool; IIS > Application Pool > ExpressPro > Properties > Identity
2. Check this account exists.
3. If it exists, ensure it is a member of the Local Servers group IIS_WPG.
4. If the account doesn't exist, create it and make it a member of the Local Servers group IIS_WPG. You can just as easily use your own designated account
5. Update the password under the Identity Tab for the Application Pool and also under the ExpressPro virtual directory found under Properties > Directory Security > Authentication Access and Control Edit, applying the password set when creating the account.
6. Restart IIS.
7. If you still receive this error make sure that the ExpressPro Application pool has been started.  If not started start the application pool and try again to access ExpressPro website.