แก้ปัญหา Ignoring file 'plesk.list.ai_back' in directory

N: Ignoring file 'plesk.list.ai_back' in directory

'/etc/apt/sources.list.d/' as it has an invalid filename extension

rm /etc/apt/sources.list.d/plesk.list.ai_back

ที่มา : https://talk.plesk.com/threads/ignoring-file-plesk-list-ai_back-in-directory-etc-apt-sources-list-as-it-has-an-invalid-filename-extension.364180/