There something on the managed switches not letting or allowing traffic to pass thru from the DAP to the other switches? 
How is the DAP connected? ISP MODEM>Router>Switch>DAP?
Can the DAP still communicate if ALL switches are bypasses as a test? 
What Hardware version is your router? Look at sticker under router.
Link>What 
Firmware version is currently loaded? 
What region are you located?