yum update 我收到以下信息：
[root@commerce-dbs-tes-1 ~]# yum update Loaded plugins: fastestmirror Setting up Update Process Loading mirror speeds from cached hostfile * base: centos.brisanet.com.br * extras: centos.brisanet.com.br * updates: centos.brisanet.com.br https://download.postgresql.org/pub/repos/yum/9.4/redhat/rhel-6-x86_64/repodata/repomd.xml: [Errno 14] Peer cert cannot be verified or peer cert invalid Trying other mirror. Error: Cannot retrieve repository metadata (repomd.xml) for repository: pgdg94. Please verify its path and try again
我知道有一个事实，有未决的更新，并一直工作，直到做到了：
yum clean all
我的系统是一个CentOS 6.7
请帮忙
由于以下原因，服务器无法validation/接受证书数据：
ca-certificates包