When Imunify360 is installed with hardened PHP, the system package manager, yum, cannot update RPMs and prevents cPanel updates.
Imunify360 hardened PHP is not used on a CloudLinux server because CloudLinux already provides hardened PHP. If Imunify360 hardened PHP repositories are enabled, they will need to be disabled to prevent issues using yum.
Disable Imunify360 Hardened PHP repos with:
yum-config-manager --disable "Imunify360 ea-php Hardened*"