App crashes with BLE

Hi. I have a problem with simple BLE data sending to ESP. When I press button "MakeDrink1" the phone app crashes and I dont know why. I am sending other data through BLE (strings) and it all works correctly so I dont know what is the problem here.

I even changed it and it still crashes. The code on the left works like it shoud, and the code on the right crashes the app

use adb logcat to figure out what't the reason for crashing.

Show all blocks and variables...