If you have requested the activation of Discovery and it is still not working, it could be very possible that something is not configured correctly under your Backlot account.
From your Backlot account, go to “PUBLISH” -> Select your player from the list -> go to “Discovery” sub-tab.
Having the "Discover Tray Click Behavior" option set to "Open in New Page" under Discovery settings will require videos to have a permalink URL in order to play. You can verify this under “MANAGE” -> Select a video -> Go to “Embed” tab and you will see the “Permalink where content is embedded” text field.
Selecting the "Open in Same Player" option under "Discover Tray Click Behavior" field should resolve this issue, unless you want to select the "Open in New Page" option, then it will be require to add the permalink value to the assets.