Installation of the plug-in went fine. I configured settings as I wanted them. The form appears fine on my most recent two posts and it captures the comments fine for both a registered subscriber and a guest.
Problem is that if a user scrolls back to a post earlier in the week, just 3 or 4 back, the form for comments no longer appears. It only shows in the two most recent posts.
Is there some setting to make it visible for historical posts as well as all new posts?
This is probably cache, please delete cache and do CTRL+F5 before check.
I ran into this myself. In case anyone is not sure why the older posts don't show commenting it is because of the setting located here: Dashboard > Settings > Discussion... In the section labeled 'Other comment settings' look for 'Automatically close comments on articles older than XX days' setting. Either Uncheck the box or set the number of days to be longer than the oldest post you wish to allow comments on. (I will attempt to attach a screenshot of the setting)
Remember to scroll down and click 'Save Changes' and then clear/purge your cache first from the Dashboard then your browser. CTRL+F5 will force a browsers cache to clear.
Hope this helps! Enjoy!