CB nightly (latest) is already default choice on our downloads menu
www.joomlapolis.com/downloads
and can be downloaded with the Download button on its right. Then install it as a normal Joomla extension (it will update the 2.1.1 version you have). Of course, backup first if it is a live site.
Ubuntu 14.04 LTS that we use on our demo server and here is not affected, and I have no CentOS box to test. If needed could setup one or get a hosting account on such a box, but it doesn't mean that it's only OS related, it must have to do with the openssl or server certificates configuration. So I think it's faster to have access to a failing server.
But here are the first 2 tests that I would like to do that you can also do and give feedback:
1. Download and install the nightly (pkg_communitybuilder_2.1.1+build.2017.01.20.01.24.41.b5adb972f.zip) and see if it fixes it.
2. If not, download the stable version 2.1
.0 (in version drop-down choose
pkg_communitybuilder_2.1.0+2016.12.18.16.28.40.cb77dc626.zip and click download button on the right of Community Builder package in our downloads, then DO NOT install it in Joomla, but unzip it, in there unzip com_comprofiler.zip and in there use the file libraries/CBLib/GuzzleHttp/cacert.pem to replance the same file on your site, then test again if it now works.
EDIT: Fixed post to take cacert.pem file from 2.1.0 and not 2.1.1.