DNF or yum output error "Failed to set locale, defaulting to C.UTF-8" on RHEL 8

Issue

• dnf or yum commands works, but it shows the following errors in English environments:

  # locale
  locale: Cannot set LC_CTYPE to default locale: No such file or directory
  locale: Cannot set LC_MESSAGES to default locale: No such file or directory
  locale: Cannot set LC_ALL to default locale: No such file or directory
  
  # yum update
  Failed to set locale, defaulting to C.UTF-8
  
  # dnf update
  Failed to set locale, defaulting to C.UTF-8