Please provide more details.
What changed? Did you do an upgrade, or make any configuration changes to your cluster?
You probably want to read this: X-Pack Authentication issue - #7 by TimV
bin/elasticsearch-setup-passwords can only be run once (unless you have complete deleted all security informtion from your cluster). Regardless of the error you are currently receiving, this is not a viable solution.
That doesn't really make sense - if you're trying to access http rather than https, it shouldn't be trying to find a SSLContext. Can you provide the full error trace? I'd like to understand what's going on here.