Change apt key server to keyserver.ubuntu.com
"ha.pool.sks-keyservers.net: Host not found"
Configuration Pull Request
Make sure that the following steps are done before merging:
[ ] A DevOps team member has approved the PR.
[ ] Are you adding any new default values that need to be overridden when this change goes live? If so:
[ ] Update the appropriate internal repo (be sure to update for all our environments)
[ ] If you are updating a secure value rather than an internal one, file a DEVOPS ticket with details.
[ ] Add an entry to the CHANGELOG.
[ ] Have you performed the proper testing specified on the [Ops Ansible Testing Checklist](https://openedx.atlassian.net/wiki/display/EdxOps/Ops+Ansible+Testing+Checklist)?