## The problem
Issue saltstack/salt#65265 (closed, 189 comments): Intermittent connection loss between the Salt master and some minions. With about 30 minions registered, a few stop responding after a while and salt '*' test.ping returns "Minion did not return. [No response]" for them. Restarting things helps only temporarily.
## What to do
Fixed upstream in 3006.16, per maintainer dwoz, along with the related issue #68297. If you see minions silently dropping off the master on 3006.x, upgrade to 3006.16 or newer. The thread also confirms this was a master-side connection handling bug, not a network or key problem, so do not waste time re-accepting keys or firewall-diving before upgrading.