Forum Post: Write failure with Supervisor timeout or Message Response Timeout

I have simpleGATTProfile running on a CC2541 based sensor.

I can connect to it using iOS BLE explorer app and BTool with the TI USB BLE dongle.

I can read the characteristic 1 (which read-write) from both iOS and BTool

I can write a value from iOS

When I attempt the same write from BTool, BLE connection times out with the error message "Message Response Timeout".

If I use HCI on the USB dongle, (by writing commands to the USB dongle on serial port): it terminates the link with "Supervisor timeout".