Comments will start to queue if you are commenting too quickly. There are two places where you can pause the comment queue: in the top progress bar and also on the History page.
The History page will display a Queued section when a queue is formed (it will not be there if there are no comments in the queue). From here you will have full control of the queue with the actions: pause/run, delete a post and delete all posts from the queue.
While the queue is paused, comments will not be made to Instagram. To keep posting comments to Instagram you will need to unpause the queue.
If you are concerned or having any issues with Instagram, pause the comment queue. Once problems have been resolved, make sure to unpause the queue to make sure your $1.80 strategy is completed!