Error: "Keyset does not exist." (4209296)

After updating the certificate on the AppServer, the below error may appear:

Server Error in '/AppServer' Application.

Keyset does not exist

System.Security.Cryptography.CryptographicException: Keyset does not exist

To resolve this error follow the steps below:

1. Open the Certificate Snap-In in an MMC window
2. Locate the new Application Server certificate
3. Right click, select "Tasks" | "Manage Private Keys"
4. Click the Locations button and select the Computer name where the site runs
5. In the textbox Enter the object names to select type in "IIS AppPool\" followed by the name of the application pool being used for this site, for example "IIS AppPool\<applicationpoolname>"
6. Select OK and then assign permissions Read & execute and Modify for user "<applicationpoolname>" (this is the name of the application pool).