If you get an error that you aren't in the sudoers file, this typically means that your user is not designated as an admin with sudo privileges.
In plain English, when it comes to some OS's like Debian including 10,11 etc.., by default the user is created without special privileges which is contrary to how Ubuntu/Mint handle the secondary user.
Let's check the sudoers file to see the problem.........
This is important as unfortunately Centos may designate a package obsolete and the replacement breaks everything (eg. you have a config file and the new replacement is not at all compatible with it and it breaks your application).
This is where disabling obsoletes comes into play, it can be done from yum but it doesn't work at the time I find.
yum --setopt=obsoletes=0 install someapp However Ifind it still installs the new app and not the one you ask for........