ubuntu server : sudo apt upgrade 할 때마다 나타나는 에러 메시지

sudo apt update 할 때마다 나타나는 에러 메시지
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perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_TIME = "ko_KR.UTF-8",
LC_MONETARY = "ko_KR.UTF-8",
LC_ADDRESS = "ko_KR.UTF-8",
LC_TELEPHONE = "ko_KR.UTF-8",
LC_NAME = "ko_KR.UTF-8",
LC_MEASUREMENT = "ko_KR.UTF-8",
LC_IDENTIFICATION = "ko_KR.UTF-8",
LC_NUMERIC = "ko_KR.UTF-8",
LC_PAPER = "ko_KR.UTF-8",
LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").
locale: Cannot set LC_ALL to default locale: No such file or directory
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mogibu@mogibu:/home$ export LANGUAGE=en_US.UTF-8
mogibu@mogibu:/home$ export LC_ALL=en_US.UTF-8
mogibu@mogibu:/home$ locale-gen en_US.UTF-8
Generating locales...
 en_US.UTF-8... up-to-date
Generation complete.
mogibu@mogibu:/home$ dpkg-reconfigure locales
/usr/sbin/dpkg-reconfigure must be run as root
mogibu@mogibu:/home$ sudo dpkg-reconfigure locales
Generating locales...
 en_AG.UTF-8... done
 en_AU.UTF-8... done
 en_BW.UTF-8... done
 en_CA.UTF-8... done
 en_DK.UTF-8... done
 en_GB.UTF-8... done
 en_HK.UTF-8... done
 en_IE.UTF-8... done
 en_IN.UTF-8... done
 en_NG.UTF-8... done
 en_NZ.UTF-8... done
 en_PH.UTF-8... done
 en_SG.UTF-8... done
 en_US.UTF-8... up-to-date
 en_ZA.UTF-8... done
 en_ZM.UTF-8... done
 en_ZW.UTF-8... done
Generation complete.
mogibu@mogibu:/home$