PSIcapture Mailroom 3.3+ (PSIfusion 3.0+) HTTP Error 503. The service is unavailable.

Problem:

When you access the web portal (locally hosted website) for PSIcapture Mailroom, or PSIfusion, you may receive the following error:

HTTP Error 503. The service is unavailable.

Solutions:

This usually indicates that the PSIcapture Mailroom or PSIfusion Application Pool is not working. Several solutions exist:

Verify Credentials on Fusion Account

Verify that the Fusion account in IIS > Application Pools > [Mailroom/Fusion Application Pool Name] > Advanced > Process Model > Identity > [Fusion Account] is accurate, as in the following screenshot:

Delete Application Pool and Remake

Remake the application pool with default settings, making sure the basic and advanced settings are as follows:

Basic:

Advanced:

Finally, make sure the identity for the user in the Process Model matches the user given permissions throughout the rest of the Fusion installation.