# yum update
The following error occurs:
One of the configured repositories failed (Unknown), and yum doesn't have enough cached data to continue. At this point the only safe thing yum can do is fail. There are a few ways to work "fix" this: 1. Contact the upstream for the repository and get them to fix the problem. 2. Reconfigure the baseurl/etc. for the repository, to point to a working upstream. This is most often useful if you are using a newer distribution release than is supported by the repository (and the packages for the previous distribution release still work). 3. Run the command with the repository temporarily disabled yum --disablerepo=
... 4. Disable the repository permanently, so yum won't use it by default. Yum will then just ignore the repository until you permanently enable it again or use --enablerepo for temporary usage: yum-config-manager --disable or subscription-manager repos --disable= 5. Configure the failing repository to be skipped, if it is unavailable. Note that yum will try to contact the repo. when it runs most commands, so will have to try and fail each time (and thus. yum will be much slower). If it is a very temporary problem though, this is often a nice compromise: yum-config-manager --save --setopt= .skip_if_unavailable=true failed to retrieve repodata/repomd.xml from ol7_x86_64_UEKR4 error was [Errno 14] curl#5 - "Could not resolve proxy: https; Unknown error
Error: “Could not resolve proxy: https; Unknown error” explains that there is a syntax issue in /etc/sysconfig/rhn/up2date config file for proxy server.
Inside /etc/sysconfig/rhn/up2date the user had below entries for proxy:
There is typo ‘https’ in the above line, when it is a http proxy being set. The format of this line should be as below:
httpProxy[comment]=HTTP proxy in host:port format, e.g. squid.example.com:3128
Change https to http and then retry the yum update.