ORA-00845: MEMORY_TARGET not supported on this system

Hi

My database version is 19 c in Oracle Linux platform. Before changing the memory parameter , memory values are as under :

memory_max_target          big integer 1424M

memory_target            big integer 1424M

After changing the memory parameter , memory values are as under :

SQL> alter system set memory_max_target=2g scope=spfile;

System altered.

SQL> alter system set memory_target=1950m scope=spfile;

System altered.

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup

ORA-00845: MEMORY_TARGET not supported on this system

What the issues? and how I will increase memory_target ? I know , I can use sga_target. But I don't want to use sga_target instead of memory_tartget.