Cursor blinking with 8GB of RAM

I would like to put 4x2GB of DDR2 RAM on my ASUS M2N-E board.
If I put 2x2GB in Slot 1-3 and 1x2GB in Slot 2, it boots but if I put another 2GB stick in Slot 4, it posts, shows me the Nethserver versions, I select the top one then it doesn’t boot, just showing me a blinking cursor in the top left corner.

The board supports 8GB of RAM, it’s the maximum. In the BIOS, it shows me 8192MB. I got the modules from another server, so they are fine.

My OS is up to date, everything is fine except I can’t put 8GB in my server.

Where should I start troubleshooting? I already tried to exchange the sticks in Slot 2 but nothing. It always boots if Slot 4 is empty. I don’t understand. If the 4th slot is bad, then why does it show up in the BIOS?

Try to boot another media with the same ram configuration.