Did you send us a debug log yesterday? I think so, because the name in the 'from' is similar to LadyLori. Normally, Steve (my son and partner) handles "out of the sky" debug logs on business days. But now that you have found me here ...
First question: what program/app is giving you the "Cannot connect to server: Server refused request:error 500" message? I ask because the debug log I have does not show that message being generated.
Looking at the log, it is almost certainly "security software" on your computer is blocking connections. CC can find the computer, but calibre cannot answer any network requests. You don't say what kind of computer is running calibre and what OS it is running, but under the assumption that it is windows:
- What firewall are you running?
- What antivirus are you running?
- If you are running the Windows filrewall, have you checked that calibre is not blocked?