kdump service failed because the system cannot resever memory for the kdump kernel when the crashkernel parameter is set to auto.
crashkernel is configured in the GRUB_CMDLINE_LINUX line in /etc/default/grub
Typically it is set as crashkernel=auto
But the system cannot set aside memory for crash kernel if the machine memory is less than 2GB, In this case, reserve the memory by hardcoding into crashkernel variable, e.g.