[bds3151]

The python library is trying to verify you have a secure connection and is unable to get a valid (trusted) SSL certificate, "CERTIFICATE_VERIFY_FAILED." This usually happens when there is something capturing traffic and is spoofing the certificate. Is this happening on all devices or are you indeed doing some traffic capture?

Edit: I did just try the addon and am getting valid responses on my android phone.

Edit #2: Looking at the log again you have the following...

• EMBY -> LINE 304: EMBY.views -> Unable to retrieve libraries: NotConnected
  
• LibreELEC -> LINE 338: URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:727)>
  
• Sling -> LINE 348: (Caused by SSLError(SSLError(1, u'[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:727)'),))
  
• EMBY Again -> LINE 646: ERROR: CCurlFile::FillBuffer - Failed: SSL peer certificate or SSH remote key was not OK(60)
  

Seems this isn't limited to Sling, so yeah I would double check the internet connection and make sure there is no MITM attacks (traffic capture)          

Thanks. It was a DNS issue. The only problem now is when I go to any new screen, it re-asks for my username/password. I had this issue with the old Sling add-on and my solution was to just re-image my pi. Log link removed

DNS makes sense. As for the username/password, once entered it should be stored inside the add-on settings file. You can try to enter it manually via add-on settings and see if that helps.
 

Not sure if this fits here or with Kodi in general but the Sling app within Kodi buffers a lot with the circle counting, disappearing, and then reappearing, counting again. Eventually the stream will return and continue for a while normally. I can go back to the Sling Windows 10 app outside of Kodi and it works without buffering. It seems especially bad with the new addon.  Does anyone else experience this? I have 3 machines and all are affected.

Buffering is what you are referring to. Once the add-on gets the stream url it hands it off to Inputstream Adaptive (automatically installed with the add-on if it wasn't before.) Each stream has multiple levels of quality, usually Inputstream Adaptive is pretty good at determining the best one for your connection speeds but if it isn't doing so then via settings for inputstream adaptive you can change "Stream Selection" from "Auto" to "Manual". Then once a stream starts, it will be at the lowest quality. From there you can bring up a menu, video options, and choose a stream quality that fits your connection speed. Unfortunately by setting this to manual you will need to pick the quality each time you play something. 

I don't think this is a problem in selecting the correct stream. Outside of Kodi, the Win10 Sling app works flawlessly at the max rate. Inside Kodi, it is highly variable and within 1 day, will buffer at least 30 times a day. How can this be a connection issue on the same machine when Kodi and the Sling addon are the only variables?