SSRS - Logon failed for the unattended execution account.

SSRS - Logon failed for the unattended execution account.

This error will occur when setup execution account's password expired or changed.

User will not be able to run any SSRS report and received the following error –

                 The report server has encountered a configuration error.  Logon failed for the unattended execution account.  (rsServerConfigurationError)

                 Logon failure: Unknown user name or bad password

fix - 

1) Go to Reporting Services Configuration Manager
2) Select Execution account of left menu and update the password and Apply the changes
3) restart SSRS services and try run SSRS report again