Convoy 12 groups not able to select sub-group

Hi flashaholics,

my new Convoy L21A arrived and i am super happy. Unfortunately, I am not able to select the mode sub-option 1.2

• From ON, i click 20 times to get into the configuration
• After normal-flash 1 time + buzz-flash (Option 1), I tab to go into the sub-menu
• After normal-flash 2 times (sub-option 1.2), I tab again
• Dark ... after 1 second, it turns into Battery Mode and the mode-selection is not saved ...

I really don't know what i could have done wrong.