When your drone is unresponsive to commands in the Pilot app or to manual operation using the remote controller, the typical cause is either some calibration that needs to be performed or your firmware is out of date. You also might be in a No Fly Zone enforced by DJI.
As a general rule, DroneSense will not prevent you from taking off. Anything preventing that will likely be either due to the hardware not connecting, or some issue from DJI that requires your attention.
Steps to Fix
If you are not receiving any messages indicating why you cannot take off through the DroneSense flight control app, power cycle all devices and try again.
If cycling the power does not address the issue, close the DroneSense app and open the DJI GO app. It will notify you if you need to perform any calibration or have a critical firmware update. Perform the updates that DJI requires and try again.
The DJI GO app will also inform you if you are in a No Fly Zone enforced by DJI. Refer to this page on the DJI website for more information about unlocking your drone.