Do the following:
DisconnectBrick(brick);
clear brick
Then call ConnectBrick as you normally would.
Execute the following commands in MATLAB:
DisconnectBrick(brick);
clear brick
Then, reset the brick (Turn it off, then on again.).
If possible, remove and replace the Bluetooth dongle.
If Bluetooth is built into the computer, restart the computer and go through the entire Startup Process in the library documentation.
Then call ConnectBrick as you normally would.