Connection to the Arduino board is no longer possible after the base shield has been attached.

Connection to the Arduino (Mega 2560) board is no longer possible after the base shield (ARD SHD BASE V2) has been attached.

Without the shield the upload of the programs is possible without problems.

But as soon as it is connected, the error message appears (but the Com connection was checked):

The following error occurred during deployment to your hardware board:

Could not connect to specified Arduino board.

Verify that the board is connected to your host, and that the host COM port number set in the model matches the COM port number in Windows.

To change the host COM port number in the model, click 'Simulation ', click 'Model Configuration Parameters'... In the dialog that opens, select the 'Hardware Implementation' pane, click 'Target hardware resources > Host-board connection' and set the COM port number.

To find out the COM port number in Windows, open Device Manager and open your board in the COM ports group.

The same problem happens when I try programming with the Arduino software. There the error message is a timeout.

Is it necessary to make changes in the settings if you want to use the Base Shield, or how to fix the problem?