Hi,
I want to install oracle DB in my laptop using on VM. VM I have installed linux red hat version 7.
Here I have used this installation guide to install linux : https://docs.oracle.com/database/121/LTDQI/toc.htm#BABJHIJD
here I have installed all the required packages and also xclock package
Then I have run #xclock command i linux but this error is occurred.
Error:Can't open dispaly :

What could be the reason for this issue?what are the solutions?