BLE disconnect not working

I made an app that receives data via BLE from a development board. The problem is whenever I press disconnect button from my app it says Bluetooth disconnected but in actual it is not disconnected unless I close the app. I have checked other topic where thy mentioned solution to disable timer and I did that but it is still the same. Every time I want to disconnect I must close the app. Is there any solution to this problem?

Dear @John_Babu,
you say you've disabled the timer, but in your blocks I don't see any reference to a clock.
Are all your blocks reperesented in the annexed picture, or some are missing ?
In the meanwhile you can try (one of) these blocks:


As an alternative, before disconnecting the BLE, your app can send a "stop sending" command to your development board.

Best wishes