I am using ubuntu 16.04 in my Dell laptop and since some time I am getting an error message
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/restricted/dep11/Components-amd64.yml Could not open file /var/lib/apt/lists/partial/security.ubuntu.com_ubuntu_dists_xenial-security_restricted_dep11_Components-amd64.yml.gz - open (13: Permission denied) [IP: 91.189.88.162 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.
while updating using command sudo apt update
. I don't know exactly why this is happening. please help me in solving this issue.