Gdm blackscreen after sleep

Help
1

Hello
I recently installed Gnome on my Nixos System.
After a short time gdm goes into blackscreen after resuming from sleep.
When I switch to tty 4 and back to tty 2 it suddenly works.
I have disabled all extensions and poweroptions i set but nothing changed.
However Hyprland works fine with hyprlock.

Kernel: Linux 6.10.10
Nixos: NixOS 24.11.20240913.345c263 (Vicuna) x86_64

Thanks for any help

2

Found the solution.
I turned my display frequency down to 60 Hz to save Power.
I think gdm can’t handle it so it goes black.
After turning it up to 120 Hz again it works.