Auto Post Images (API) Plugin not quite working

Hello.
I have installed this plugin

but can’t get it working

Here are my settings for the path and url:
Image directory: /home/accountname/public_html/wp-content/uploads/images

Thumbnail directory: /home/accountname/public_html/wp-content/uploads/images/thumbnails

Cache directory: /home/accountname/public_html/wp-content/uploads/images/apicache

This is the directory used by the plugin as cache location when generating thumbnails. Ensure that the plugin has write permissions for this folder.

Image directory URL: https://www.domainname.com/wp-content/uploads/images/

This the url to the directory where the images are stored.

Thumbnail directory URL: https://www.domainname.com/wp-content/uploads/images/thumbnails/

Can anyone see what I might have screwed up on here? All have 755 permissions set.
Thanks.