CHIRP

This error is indicating that CHIRP is unable to make a secure connection to repeaterbook's server. The error in the log indicates that this could be a couple different things, potentially a local security/antivirus application blocking access, or even that your clock is wrong. I also just tried it locally and can confirm that it works for me.

The repeaterbook website also indicates as of this moment that some work is being done, so it's possible that you caught it at a bad time or something. Can you check your computer's clock and try disabling any "security" software you have to see if that's related?