Over the last week or so, I've noticed that a number of my Windows 2008 servers have started displaying alarms for "could not establish communication with the Server". In every case so far, the fix has been to apply the reg key for setting the default secure protocol as outlined in this article: support.site24x7.com/portal/en/kb/articles/how-to-check-if-tls-1-2-is-enabled
Looking at the agent logs on a couple of the servers, this seems to have started around the 6th or 7th of July. The logs from those days, and before, were clear of an issues. The logs generated after that are showing various errors: 12002, 12007, 12175. But, as soon as I apply the reg key mentioned above, the errors clear and the agent begins communicating properly again.
Did something change on the Site24x7 side that may be causing this? Obviously I have a fix, I'm more curious about why this began occurring out of the blue.