Okay. You definitely have a random issue but your problem is not my plugin or anything with WordPress (probably)… you have:
1. a DNS routing problem on www.
2. a server problem
3. possibly an .htaccess redirect problem
4. something with an https certificate isn’t configured right either (using mxtoolbox.com to test)
https://www.kiwiearthmother.com (note the www) initially broke when trying to load. It later loaded okay. https://kiwiearthmother.com loads fine.
I’d talk to your host and/or a developer and look at your host error_log’s. See if there’s anything in there that can shed some light on what’s going on… If it’s a DNS problem then you need to either talk to your host or your registrar (where you bought the domain).
As far as the image. This is the one being pulled for your homepage: https://kiwiearthmother.com/wp-content/uploads/2015/03/mother-earth3-320×228.jpg
It is too small for FB as per their rules… so it’s using this one instead https://kiwiearthmother.com/wp-content/uploads/2015/03/Profile-picture3.jpg
For the home page if you set a fallback image, that’s big enough for FB, in WPFBOGP settings, then FB will use that image for the homepage.
Single posts will look first for a featured image, and then go to images it can pull out of the content and always fallback to whatever the fallback image is in settings.
This is all described in the plugin description but FYI.