Description of problem: When setting up a new certificate with the current 0.20 package in EPEL this error is returned. > Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA. Version-Release number of selected component (if applicable): 0.20.0-1.el7 How reproducible: 100% Steps to Reproduce: 1. run `certbot` 2. pick a domain to setup 3. see error Additional info: https://community.letsencrypt.org/t/solution-client-with-the-currently-selected-authenticator-does-not-support-any-combination-of-challenges-that-will-satisfy-the-ca/49983 on Jan 9, 2018 letencrypt disabled the mechanism that older certbot used to validate the domain. Certbot 0.21.0 was release to add a new machnism to the apache/nignx plugins. https://community.letsencrypt.org/t/certbot-0-21-0-release/50725
we now have 0.21.0