Wired internet stops after time

so i have a RPI 3b+ all setup everything works but i have a problem,

my raspberry pi after some time stops the wired conection the blinking dots go out and i need to restart my rpi can someone please help me

is the board fualty do i need to set the ip tp static or smth if yes how

Hi

You might be under powering the pi
Try a different 5v PSU that offers more amperage

Also read the documentation, in ragards to common requirements for HA.
I.E min 2 GB Ram … your RPI 3b has , how much ?

If it is a crash of RPI due to lack of memory a temporary fix would be to increase your swapfile. Search the forum for that. You haven’t stated your setup eg SD card or SSD. What’s memory useage like in hours leading up to stoppage.