While syncing centos 7 os repo below error message is shown if download policy is “Immediate”. Sync is success if the policy is “On Demand”. There is a squid proxy between katello and internet (centos mirror)
Katello::Errors::Pulp3Error: [Errno 104] Connection reset by peer
smartproxy = 2.1.3
katello = 3.16.1.2
foreman-tasks = 2.0.2
Detailed error message here - https://gist.github.com/rokbasnr/207035b15db27fefdd365859ee90ece9