Cannot login anymore

Every time i try to login i see the gui for one second and then i get logged out. The desktop app does nothing. So i made the 40 second reset. The box was constantly blinking for hours so i turned it off. Next time i made the reset the box blinks for a few minutes. Login with the browswer works now but it says the drive is offline. And after one minute i get logged out again. So i made the 40 second reset again. It is blinking since yesterday…
This thing is only a few months old.
I dont trust these things so i luckily made my real backup on an external hard drive.
Now i ordered an Synology sorry.
Maybe someone has another useful hint?

@Fuchsi
Have you visited the Learning Center and looked at all the information provided there?

I forgot to write that the Mycloud Home was correctly installed and worked for a few months. I dont use it very often so i cannot say exactly when this thing stopped working.