Thanks for the details. It's the first time I see this particular error, but here's two likely solutions:
- First double-check the firewall isn't the culprit. The REAPER process should be allowed full, non-intercepted access to internet.
- There's an option in ReaPack to disable the SSL certificate checks entirely. Try this if it still fails: https://i.imgur.com/x73pzPo.gif.
I hope this helps.