Why is an error returned when trying to login into BUI?

Environment:

Agent Browser User Interface (BUI)
Oracle B2C Service, All versions

Issue:

Error encountered when logging into Agent Browser UI (BUI):

404 Not Found
The requested resource was not found.

Resolution:

In order to resolve this issue, you will need to enable profile permissions to authenticate on Agent Browser UI. Use the steps below:

1. Log into the Oracle B2C Service console using an administrator account
2. Navigate to Configuration -> Site Configuration -> Profiles
3. Open profile(s) assigned to the staff account experiencing the error
4. From the ribbon click on "Permissions"
5. On "Administration" tab, check the option "Account Authentication" under Agent Browser User Interface
6. Hit Save

See also, the Assign Agent Browser UI permission in profiles section in online BUI documentation.