Can you try to boot the server with Minimum to POST configuration? Minimum to POST configuration is the configuration that has the minimum components required to complete POST. Typically, the minimum to POST configuration is PSU1, CPU1, memory module in A1 slot, and the default riser without expansion cards.

ok thanks for the suggestion, i'll try it

sorry, I've followed your advice, but had a problem configuring the memory

If it is showing memory issue can you try with another DIMM

Along with what Shine suggested I'd also try to plug out CMOS battery.

Thank you, i will try