U-boot doesn't start when start button is pressed

Please follow the steps to put your module in recovery mode and then do the flashing as described here.

Already my problem is that I can not see the screen below.

Apalis iMX6 #

When I press the ixora power button, only the following screen is displayed.

Commercial temperature grade DDR3 timings. 
  Trying to boot from MMC1

Are you able to put the module in recovery mode?

I am not able to put in recovery mode.

Then the module could be defective. Fill the RMA in this case.