Is the error start coming after performing and Hardware or configuration change? Are you only seeing machine check error or you see an IERR also. Did you have latest iDRAC and BIOS installed on the server?

You can refer below link for some troubleshooting steps

https://www.dell.com/support/kbdoc/en-in/000137438/dell-poweredge-resolve-cpu-1-or-2-has-an-internal-error-cpu-ierr-on-servers#:~:text=System%20Issues%20Description-,The%20CPU%20Internal%20Error%20(CPU%20IERR)%20or%20CPU%20Machine%20Check,instruction%20from%20a%20system%20component.