Impossible to take a picture without the red icon

[yonafunu974]

Hi !
First thanks for your awesome work !

Everything works fine except when i try to take a picture nothing happens. When i do a long click on the capture button, the icon becomes red and this time i can take a picture (but i don't want download raw...).
Have you an idea why ?

QDD 3.5.4
Nikon D600
MR3020 Tp-link

[hubaiz]

Is there an SD card in the camera?
Is the AF button red, if yes then long press it.