'yum update' 命令返回错误： "This system is registered with an entitlement server, but is not receiving updates.You can use subscription-manager to assign subscriptions."
Issue
即使系统已正确注册，yum update 命令仍会返回以下错误：
This system is registered with an entitlement server, but is not receiving updates. You can use the subscription-manager to assign subscriptions.
Environment
- Red Hat Enterprise Linux
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