Can you confirm if you are using Desktop Notifications or CLR Browser?
If you are using CLR Browser, did you restart DeepBot after starting up OBS.
I would say try and hit the preview button and see if the notification pop's up. If not, restart OBS and try again.
Generally CLR Browser creates a connection with DeepBot on startup or when you disable and enable the scene (if it is not a global source)
If you restart the Bot after that, the connection is lost and needs to be re-established by unchecking/re-checking the notification source.
You can always use the Preview button to confirm if it is connected.