Failed to start light display manager after fresh installation

I have an AMD driver and AMD radeon graphic card.
I dit a brand new fresh installation with manjaro cinamon with a Live usb and no problem. So i reboot, first time and i have this error.

Failed to start light display manager (in red)

So please can you help me ? What should i do to fix that ?

So with sudo lightdm, i can start and see the desktop.
but after a reboot, same problem.

Maybe have a look at

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