issue updating repo

good day, I'm having issues updating software and/or installing programs using the command yum, the error is

Curl error (6): Couldn't resolve host name for http://content.example.com/rhel8.0/x86_64/rhcsa-practice/errata/repodata/repomd.xml [Could not resolve host: content.example.com]
Error: Failed to download metadata for repo 'updates': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

Please help me