Starting on August 11, 2018, our AD Connector stopped synchronizing users into Samanage. When I logged in about a week later (after discovering the issue), I was prompted to change the password on our administrator account for the Centrify admin portal. After doing so, I was able to log in.
I did some troubleshooting for a couple days, but was not able to get the connector running again. After attempting to change to a different admin account (Samanage admin account vs. Centrify), we have now found that none of our users can authenticate against the Centrify SSO page, and must instead log in through the Samanage local login.
Centrify support has told me that our use of Centrify with Samanage was never supposed to be a long-term solution, but rather a 30-day trial, after which we were supposed to buy a support contract in order to use the full application and gain access to support. However, our Samanage rep has said that, although support is limited to Community Support only, we should be able to use Centrify with Samanage on an ongoing basis for no cost.